Eastern Front Defensive Abilities
Looking at the Wehrmacht Defensive (Community) Doctrine and then to OKW Luftwaffe Ground Forces/Fortifications is pretty insulting. Tank traps and trenches are two separate abilities for the Wehrmacht, but OKW get both plus flak emplacements in a single ability? Surely we can similarly consolidate underused and underpowered commander abilities into each other to open up tactical diversity?
I think that increasing the availability of defensive options like tank traps could be a very good thing for the metagame, especially in large team games where tank traps in particular can help break up the ridiculous tank blobs. Perhaps these abilities could become valuable in the minds of more players, rather than just filler between the call-ins and the air support.
Listed below are some possible solutions; they don't have to be all-or-nothing if they are partially salvageable.
Fold (Wehrmacht) Riegel Mines, Tank Traps, and Trenches into one ability. Since Wehrmacht Defensive (Community) Doctrine has two of these, it'd need a new ability. I'd suggest Incendiary Bombing Run, a thematic ability which only shows up in one other doctrine and an additional munition sink.
Fold (Soviet) Anti-Tank Gun Camouflage, Tank Traps, and PMD-6 Mines into one ability. Same goes for the Soviet Defensive (Community) Tactics, which has two of these abilities. I'd suggest the KV-2 Heavy Assault Tank, a thematic ability which again only appears in one other doctrine and would give this doctrine some late-game potential.
Other obsolete or awkward abilities
There are many other abilities which haven't been looked at much, or have fallen to the wayside as design paradigms for CoH2 have changed. Culling some abilities or units for others (Irregulars to AT Partisans, for example,) can help make game design smoother and bring alternative strategies closer to the forefront of the CoH2 metagame
Wehrmacht
Replace Relief Infantry with Mobile Defense Ostruppen
The psuedo-defensive ability of Relief Infantry is incredibly clunky to use with the Wehrmacht's 4-man squads. Why not just let the Soviet ability which works better be unique, and allow players to gain Ostruppen squads directly instead of having to pay munitions and manpower (for reinforcing units lost to fuel Relief Infantry) for those mediocre soldiers?
Swap LMG Grenadiers for Assault Grenadiers in German Mechanized 250 Halftack
This is a no-nonsense, straightforward change which will allow assgrens to live in more than one commander. Honestly, why fill the 250 halftrack with basic Wehrmacht infantry? On that note...
Give the 250 Halftrack... something
Manpower cost reduction is a given, but even so, there is little point to this risky doctrinal clowncar. An mg, an upgrade to the 250/7 mortar halftrack, a recon ability, ability to drop panzerschreks, something.
Replace Close Air Support Doctrine abilties with their loiter counterparts
I personally felt that this is how CAS should've been balanced. Bigger abilities make munition transfer more relevant, loitering introduces counterplay, and it gets rid of the silly "dodge or be murdered" game which CAS currently presents.
Fold G43 Upgrade Package and Model 24 Stun Grenades into the same ability
Another case of extending rarely-seen abilities together to promote their usage. This would very likely come with an increased munitions cost for the upgrade, but it'd still be interesting. Give Elite Troops the stuka suppression run/fragmentation bombing run or something.
Soviets
Fold Hit the Dirt! and PPSHs into the same ability
Hit the Dirt! is very rarely seen, which is a shame. Not much else to say. Give Guard Rifle Combined Arms and Conscript Support Tactics the DShK or something so that unit can see more use as well.
Consolidate Vehicle Crew Repair and Repair Stations
Soviets have so many repair options, it's rather silly. Fold, replace, or whatever you like, but at the very least Soviet Industry doesn't need two of them. Give them IL-2 strafing support for a proper munition sink.
Replace Conscript Repairs with For Mother Russia!
Hell, while we're at it, remove the other widespread repair ability to something more immediately valuable for conscripts, and to make the remaining repair abilities more valuable.
Add near-instant reinforce time to Rapid Conscription
The instant reinforce time of the British Air Resupply Operation would be a brilliant addition to this rather bland ability. It just makes sense.
USF
Do SOMETHING to Elite Vehicle Crews
This might be the single most useless ability in the game? 90 munitions to make something you don't ever want to see away from a vehicle half-decent in combat? Make it into a weapon-rack upgrade, make it an automatic upgrade and/or a half-sized upgrade for Rear Echelons, just don't keep it how it is.
Replace USF Recon Sweep with M10s for Recon Company and Bulldozers for Mechanized Company
This ability is incredibly redundant with the Major, although I do recognize that there are some differences. These two commanders are widely seen as the weakest that USF has right now, and a lot of that comes down to poor late-game presence. Giving them sturdier call-in vehicles can help with this issue.
Fold Riflemen Flamers and Riflemen Flares into the same ability
Flares are very rarely used, and this could make way for inserting Riflemen Field Defenses into Rifle Company, which seems rather appropriate and would further diversify defensive options like the Eastern Front changes I proposed.
OKW
Fold Valiant Assault and Breakthrough Tactics into the same ability
Who uses Breakthrough Tactics? Shouldn't the infantry-focused Breakthrough Doctrine have an infantry-focused ability? They make sense together, especially with the Luftwaffe Doctrine's focus on capturing territory.
Fold Radio Silence and Artillery Flares into the same ability.
Similarly, who uses Radio Silence? Both abilities firing at the same time fit with each other, silently spotting for a slightly sneaky attack. Mostly though, it'd free up an ability slot. I'd suggest HEAT shells or even Wehrmacht's Breakthrough (Encirclement Doctrine) for added 'elite' capabilities.
TL;DR
I hope that Relic revisits old abilities with how the British Forces were designed in mind, making abilities more elaborate and useful for all factions. Feel free to discuss my ideas or provide your own. Just please be nice! These were suggested more from a design standpoint than a balance standpoint, although I'd like to think that most of these are fairly balanced.