First I will talk about the individual abilities of each commander and then give a short overall evaluation of the commander. At the end I will rate the commanders against each other.
Special Operations Doctrine:
Radio Silence: It sounds like it could be used well by a good player for an interesting flank, but in reality it will probably not happen very often that you catch someone by surprise with an attack that he would have only noticed if he was visible on the minimap but cannot see otherwise and it having a big impact. Even if you don't see them on the screen either, you can usually still hear vehicles driving or other kinds of sounds. Overall I think this ability is not very good.
Infiltration Tactics: Can be very powerful and is very cheap as well. Very good to clear buildings and good against blobbers and sometimes to flank static weapons. Cannot be used all the time, is fairly predictable by mobile forces and is only powerful on squads without losses, but these seem like fair tradeoffs and the ability is generally still good.
Infrared StG44 Package: Most of the time this feels like a downgrade over the MG34 on Obersoldaten and thus a waste of munition. Turns them into a more short-medium range unit, but it will still not really help them against Shocktroops and for everything else the MG34 seems already good enough or even better.
Artillery Flares: Very useful ability, similar to Scout planes.
Panther Command tank: Even more expensive than the Panther, but the ability on it that is compareable to Mark Vehicle is reason alone to get it over a normal Panther. The aura is nice, however in 1on1s you probably won't have many other vehicles in the same time because of lack of fuel. It also buffs team mates though which makes this tank a lot better here. At veterancy 4 and 5 it improves the aura instead of the tank itself like the normal Panther, so this is something to consider. You also don't really profit from it being a call in in the same way as other call in tanks do, since you will probably want to go for T4 anyway as this commander lacks call in infantry and probably need Obersoldaten for that reason. If the Infrared StG44 was more attractive this would be another reason to go for T4. Overall I still like the Command Panther though.
Overall: This commander seems average to me. It has a few decent abilities, but none that make you feel you want to go for it every time, especially since Infiltration Tactics is also found in Scavenge Doctrine. I think it is also better suited for Team games than for 1on1s.
Luftwaffe Ground Forces Doctrine
MG34 HMG: Gives you a machine gun that you would otherwise not have in your army apart from Kübelwagen. For some people this is essential and reason enough to pick a doctrine like this, others can probably also do without, some will make it dependent on the map or situation. Nothing to complain about here though.
Heavy Fortifications: Not very useful in the current state. The Flak emplacements are expensive for what they do even if they work, but often they will just hit the ground or even hit your own units instead. They can also be very easily decrewed especially by Snipers and potentially even turned against you. Trenches don't seem too useful either, I guess you can consider them for Rocketlaunchers, but you cannot redirect their firing arc inside. Tank traps are ok, but not a lot of people will use them a lot.
Fallschirmjäger: They can be very good, but they are also the most expensive infantry unit in the game. In long range combat they are a bit worse than Obersoldaten, but they don't need certain teching and are usually available earlier. On some maps their ability to spawn in buildings is also a great advantage. They also scale nicely with veterancy and have a Panzerfaust. Personally I like them.
Valiant Assault: Pretty expensive, but it lasts quite a while and the bonuses can be very useful in certain situations. Can be good, but is not something you will use all the time.
Airborne Assault: Pretty good, as you can buy a Fallschirmjäger squad with munition instead of manpower if you have an excess amount of it. The strafing run ability is sometimes good, sometimes bad, as you cannot target the direction. Sadly can only be used on capture points that the enemy owns, but it is still good.
Overall: I think it is one of the better commanders of OKW. Apart from one ability all are useful and the Fallschirmjäger and MG34 can be enough reason to pick this commander.
Breakthrough Doctrine:
Breakthrough Tactics: It seems very situational to me. Surely it can be a big advantage in those close games where you need to decapture that VP to win the game, but personally I tend to forget then that I even have this ability because you probably will not use it otherwise (not blaming the ability for this though ). I actually haven't even used this ability once yet, and I don't think anyone is ever going to pick this commander just because of this ability.
Sturm Offizier: Not sure about this one, as I do not know the exact buffs it gives to units around. I don't know why this unit doesn't gain veterancy either, as other units like the Major do. I think the drawback of making all your units retreat if the wrong model on the squad dies is too big and rather ridiculous, if at all it should just remove its aura and abilities but not make your units retreat. Currently this means you can only use them well behind your other infantry (preventing you from using the active abilities usually) or to stand next to your Infantry Support guns, which it can also help defend with its force retreat ability. Can also sometimes use it to make that annoying machine gun from the enemy retreat. The combat buff doesn't seem that strong that you couldn't just instead build another regular infantry unit. Personally I am not a big fan of this unit usually.
Panzerfüsiliers: It is a pretty good unit, but it only really starts to shine once you upgrade it with the G43 rifles, which makes it actually rather costly on munition. It is durable and the extended sight with the upgrade is very valuable, and it can be used in bigger numbers than Obersoldaten or Fallschirmjägers, even though those units seem generally stronger. Sadly both the Stielgranate and the Anti-tank grenade bug out more often than they work, which is a big issue. Overall still a good unit, although personally I favour the other doctrinal infantry units.
Assault Barrage: Not completely sure about this one. It costs relatively much and has a very long waiting time before it appears. It also lasts very long and ends with a huge smoke barrage which can be very useful, however I have never seen something die to the artillery itself, it seems more like a denial option. Sometimes though I have seen shells land next to units doing more or less nothing to them... the ability can also be only used on capture points the enemy owns. I guess it can have its uses, but overall I find this ability mediocre at best.
Jagdtiger: Extremely expensive, but also very powerful. Usually I only consider this unit when I have to fight against ISU-152 commanders, as it is the only reliable counter for this unit currently and pretty much forces you to pick this commander a lot of times, especially in team games. It is very suspicible to flanks, so you have to make sure you can defend it with Panzerschrecks, mines or other anti-tank weapons. It is also very easily crew shocked, so you shouldn't overextend it against massed anti-tank weapons.
Overall: The Jagdtiger is reason alone why you will probably have this commander in your selection list in the very least. Apart from that I think it is a solid doctrine, but if it wasn't for the Jagdtiger I would probably not pick it currently as the Luftwaffe and Scavenge doctrines seem more attractive if you need doctrinal infantry.
Elite Armored Doctrine:
Signal Relay: Don't know, never really used it a lot, I guess it can be ok, but nothing you would pick the doctrine for, as Artillery Flares or the "Uhu" will be probably more useful for this purpose.
Emergency Repairs: I haven't used it yet, it seems very situational. If you have a critical damage you most likely need to repair your tank completely with Pioneers anyway, and the drawback on the ability means you cannot really use it on the frontline, so the amount of situations where this tank allows you to rescue a tank that would otherwise be lost seems very limited.
HEAT shells: These seem very weird, as this seems to influence the whole behaviour how the tank shells fly. I am not sure this ability even works properly right now. In theory it would seem ok though, even though situational.
Panzer Commander: I don't find these very good. If you upgrade them, you cannot get the Machine gun upgrade on a tank, which is a big drawback. The increased sight range would seem useful mostly on the Panther. The artillery thing seems too expensive and of limited use.
Veteran P4 call in: Terrible. They are worse than the regular Panzer IV, they only come very late in pairs even though at that stage they already are too weak in most cases, their veterancy that they have is random meaning they can come without any and it is not as good as on regular Panzer IV as they don't get armor upgrades and it will probably not even let you skip a tech because you will want T4 for Obersoldaten as this commander lacks doctrinal infantry.
Overall: In my eyes by far the worst commander of OKW and probably one of the competitors for the award of the worst doctrine in the game. All the abilities are either useless or incredibly situational and even then of limited use. No reason to pick this commander.
Fortifications Doctrine:
MG34 HMG: Same as in Luftwaffe.
Heavy Fortifications: Same as in Luftwaffe.
Field Defenses: It gives you bunkers and S-mines. The bunkers can be nice, it overlaps a bit in role with Flak emplacements but since Flak emplacements are crap right now it has its use. For some reason they don't let you upgrade them to medic or reinforcement bunkers like in Ostheer though. S-mines overlap a bit with regular mines and personally I would rather like to have Teller mines to supplement the OKW army, but some people love the S-mines and I guess it is a matter of personal preference.
Pak 43: Very situational, on some maps it can still be useful, but overall I think it is overnerfed in range and too vulnerable for the price. I also think it comes a bit too late in the current state. However, if you manage to just kill 1 or 2 tanks, it is probably still worth it.
Zeroing Artillery: A bit weird because it gets better if you see the target area, however you don't want to stand too close to it because you don't want to get hit by it, which makes it a bit hard to use. It also tells your enemy exactly about the radius, so your enemy knows exactly where he can go and where not. It is also extremely expensive. If your enemy stays in it it can be devastating, but overall I find this very situational and probably too expensive unless you don't know what to do with your munition anyway.
Overall: It overlaps a bit with the Luftwaffe doctrine and other abilities in the game, but there can be situations where this commander is useful. If you like to play defensively and maybe attempt something like a tech rush, this commander may be interesting. In the end a matter of preference.
Scavenge Doctrine
Thorough Salvage: Additional ressources on salvage can be very useful, however the increased salvage duration can be a massive drawback, as you may not have the time anymore to salvage things in the front line before the enemy comes back (I like to salvage decrewed enemy support weapons sometimes before he comes back). Often I find this ability does more harm than good.
Jäger Light Infantry: Very powerful and probably the main reason to pick this commander. They are priced between cheap and elite infantry, but they fight very well and have extended vision which is nice. Booby traps can be also quite nice, they can spawn in buildings, salvage and sprint. They sadly don't have grenades or anti-tank snares though, and they cannot pick up weapons or even medkits which is probably a bug. Overall very good though.
Infiltration Tactics: See Special Operations Doctrine. Have to add though that these don't apply to Jäger Light Infantry which makes it a bit worse, as you probably will rely a bit less on Volksgrenadiere.
Ostwind: It can be useful, but personally I am not a big fan of the Ostwind in general, as I think it is too expensive for what it does in comparison to other alternatives like the Luchs. However you might skip T4 with this doctrine, which means you can use the Ostwind instead of the Luchs.
Howitzer Barrage: Very powerful if you have lots of munition. In comparison to the other artillery call ins that OKW has it is definitely the best in my opinion. On the other hand enemies will probably not just stand around in it all the time. According to other people it is currently broken against American base buildings, so this probably will be fixed eventually, personally I have never tried it out like that yet as this seems lame.
Overall: This is surely one of the stronger doctrines again already because of the Jäger Light Infantry. It overlaps in role a bit with the Luftwaffe doctrine and I think there are arguments for both doctrines, in the end it is a matter of preference (or money; the Scavenger Doctrine has to be bought with money if you don't have luck with war spoils).
Personal overall Ranking
1. Breakthrough
2. Luftwaffe
*. Scavenge
4. Fortifications
*. Special Operations
6. Elite Armor
I put Breakthrough at number one because I feel it is currently mandatory to equip it because of the ISU-152 meta, otherwise it would be probably ranked lower.
Luftwaffe and Scavenge Doctrine are a matter of preference in my opinion and on a similar level, you could also reverse the order of the two easily.
Fortifications doctrine can be interesting for defensive players or when you find you need a Pak43 because you have no fuel to defend from tanks (although I find you mostly lose in these games anyway), while Special Operations has Infiltration grenades "for the poor" among us and good potential for team games if at least one guy picks it.
Elite Armor is just plain wrong.