Would be cool if you would read the post, since I spent some time writing it.
Infantry Section
The IS is a weird unit that is capable of over- and underperforming within a matter of seconds. Good when still and in cover, dangerously squishy when out of it and totally useless when on the move, this squad has so many things against it that the price of 280 and the high reinforcement costs are very questionable. In addition, since this unit is meant to be the baseline infantry and scales well with Vet, it is especially astonishing how much it lacks in control and utility.
The artillery upgrade is interesting, yet it suffers from the faction specific indirect fire problem which will be mentioned later. The medkit upgrade is nice since the usage is free. However, it is funny that, while Relic obviously acknowledged the need to activate the healing ability manually on the USF medic truck as demanding an unnecessary amount of micromanagement, and therefore plans to remove that functionality with the next patch, they still thought it was a good idea to make the Brits even more micro intensive. The medic ability needs to be unlocked on a squad and that squad needs to be near the unit/squad you'd like to heal. And the healing unit needs to be out of combat for a specific time.
Well if that isn't rather inconvenient I don't know what is. It works ingame, of course, but it's demanding even more microing attention from the player than the USF medic truck did. Now strategic planning for small abilities is also required. Touché.
Furthermore, someone needs to mention the comically heavy reliance on RNG for the Tommy squad. I had engagements where basically the first salvo headshotted a model in the enemy's squad. I also had engagements where my IS in cover lost against a Sturmpio squad in the open at medium distance. They just didn't hit shit while getting slowly ripped apart by the assault rifles.
Another big, big flaw of the IS may be the fact that they don't have anything to deal with early vehicles and garrisoned units. In fact, they don't receive anything directly combat related at all unless you research the upgrades in your base. And even those don't help against garrisons. In addition to only having 4 models per squad baseline, being a highly situationally perfoming unit and bringing nothing to the field than a nice voice-over, 280 MP seem far too high for them.
Oh and again, squad size increase is a noob trap, since it doesn't change the reinforcement costs at all and you will lose even more models ON TOP of the added tech cost. Bummer, really.
I would reduce costs and/or give them some means to deal with vehicles, like Riflemen. Or like Russians that can research anti-tank grenades. Just give them SOMETHING to unlock via veterancy, something that is not locked behind yet another resource sink in this clunky to manage faction.
Universal Carrier
This unit is just plain bad. Why? Not particularly because it lacks damage... it's just the way the damage is being applied and it's total lack of useful control or support abilities. It is far more heavily armored than the Kübelwagen, yet the Kübel is so good because of the suppression.
In addition, without any upgrade, the Carrier takes his sweet time to inflict meaningful damage to any half decent player. And by the time you get your flamethrower upgrade rdy - which is very effective right now - you can definitely expect some Schrecks, Raketenwerfers or even an early scout car to hit the field at the same time. Which means it's window of opportunity is very small. The unit also feels clunky. Like the Kübelwagen, it has to face the enemy to shoot, but it is slower, which means it's constantly turning and just feels hard to micro around many maps.
In addition, it lacks any obvious duty except for dealing damage and hoping it does something useful before it gets inevitably killed before even vetting up to 2. Locking the self-repair behind vet 1 is also not very "balanced", since it doesn't feel like a powerup of any sort and just leaves a bitter taste behind as of why it isn't available from the start. This is further pronounced by the Engineer dilemma the UKF faces. More on that later.
My solution would include, but would not be restricted to, making the unit faster (speed, turning etc.) or giving it some real purpose. Make it able to capture points for example, like the Panzerelite Kettenkrad. Or raise it's cost and make infantry able to shoot out of it. Or whatever.
I can't see anything else so far that is a unit specific problem, therefore, let's get to the more complex problems.
Conceptional flaws, lack of options despite having to chose.. .
Playing the Brits feels clunky. That's it, I said it. You have less stuff to tech compared to the other factions since you basically skip the common T3 stuff and jump from T2 to T4. This creates a big hole in the game pacing for Brits, which is further amplified by the high MP bleed you suffer due to the overpriced Infantry Sections.
As an UKF player, you have to deal with a substitute for T3, the Armored Car. You have no mobile reinforcement option, you have to light artillery (more on that later) and my personal biggest problem is you have nothing to fill the anti-infantry gap between the problematic Universal Carrier and the strong but expensive and late Centaur. OKW, another faction without many vehicles, manages to fill the gap between Kübel and Luchs with the AA Halftrack. The UKF Armored Car is good against vehicles, but obviously as underwhelming against infantry as the Puma. But where the OKW player can decide against a Puma and for the AA Halftrack, the UKF player has to decide between the Armored Car and... Bofors. Bofors is AWESOME (yaya, we know) against infantry... but it's an emplacement. Something that suffers heavily against enemy indirect fire. It just sits there, ready to be avoided by your opponent. And locks the UKF player out of having the Armored Car.
It is nice of Relic to enforce a more meaningful decision making as a core necessity, but I think it's the wrong approach. The correct way is to give the player options that are all good, so he has to decide. Like with the Commanders (theoretically). UKF however forces you to chose between stuff that is not equally as valuable, at least not for me. The options are clear, no Bofors in 1v1. Then you drive around with your Armored Car and wish for another version of it, with better anti-infantry capabilities...
And again, the only mobile reinforcement option is doctrinal.
Indirect Fire Options, or lack thereof
I think it's kinda ironic, that UKF is the faction with the biggest problems here. And I am not talking about the awesome Commander Abilities that use offmap artillery. I am talking about the core faction mechanics.
As an UKF player, you have the option between your base howitzers and a mortar emplacement. That's it. The base howitzer barrages come for free, therefore they basically can't really be buffed without the danger of becoming obnoxious. The delay until the first impact is high, therefore the artillery is useless against enemy pushes, flanks and all other sorts of tactics that involve moving one's units... Hurray!
The mortar pit is performing well within it's range, no doubt about that. Yet, the price is hefty and again, it's immobile because it's an emplacement. Not even talking about the population slots it occupies. It's a problematic manpower investment in a faction that more often than not finds itself unable to build tanks due to not having enough manpower while floating 200 fuel in mid-late game.
UKF lacks light artillery. They lack something like the leiG, the mortar squad etc. This is extremely annoying, since your opponents don't hesitate to use those to great effect against UKF. Your infantry is not durable enough to approach enemy indirect fire sources to make them stop bombarding your HMG and emplacements. But you also cannot fire back. It can become really frustrating. Light indirect fire options are a must in the current game, since those may not be extremely powerful, but they become that if your opponent can't counter them properly. UKF seems to be unique in that regard.
Do I really have to mention the Sexton? Even if it would be a better unit, it still falls under "heavy artillery" and doesn't solve the factions problem.
Engineer Dilemma
It's crazy. UKF is the only faction where players don't start with a builder unit. UKF, as the faction with the least infantry units on the field (normally) in early game, is the only faction unable to utilize barbed wire or mines to cut off certain paths and areas in order to minimize flanking. Amazing. The wire comes with T2, after the playing field is more or less devided amongst the players already and you have your hands busy microing your squishy units to the best possible effect. Between repairing your armored car or replacements and running around capturing territory while your main infantry is trying to stay in cover somewhere to not get eaten alive by pretty much everything with an initial cost above 200 manpower, the engineers rarely find the time to make the UKF player's life easier. The mines are good tho.
In addition, UKF lacks tank traps. In my opinion that's also a no-go for such a vulnerable, expensive faction but whatever. Maybe we will get a Commander for that.
Game Pacing, Difficulty
There are basically only two options to chose from in the early game in 1v1. IS, HMG, Tech and IS, HMG, IS, Tech. No AT gun in T1, no useful vehicle (see Universal Carrier section earlier in the post)... Plus, the micro intensive med kit stuff is being unlocked with T2 as well, so you will need it soon. Your infantry sections don't effectively traverse into mid game due to the total lack of useful abilities. No grenades without tech, no AT stuff at all, no flamethrower upgrades, nothing. Again, you have no "normal T3" and only the Armored Car. In order to get to the point where you start to become good, you need a sniper and T3, therefore unlocking Brens and PIATs is another heavy investment.
Losing an IS in the early game rips your game pacing wide open and makes you vulnerable to basically everything your opponent can come up with. You micro has to be on point all the time when playing Brits, even more so than with the other factions.
Once you enter T2, you immediately have to chose between sniper and AT gun. Both are good units, but at that point you will most likely face an early vehicle heavier than a Kübel plus infantry with either Vet and assault rifles or LMGs or even flame throwers. A very difficult decision. You also have to look at your fuel amount in order to have a good timing on your Armored Car. Building it often get's delayed by the notorious manpower shortage, while you always have the fuel...
Hampered by the inability of the Infantry Section to excel at anything noteworthy, the mid game is a pure micro management orgy with the advantage always on the opponent's side. Be it indirect fire options, the ability to clear garrisoned units, having a vehicle against infantry, being able to reinforce in the field with a halftrack and other stuff, UKF players always somewhat play from behind.
Lastly, late game UKF is overrated in 1v1. You will most likely only have the fuel for one tank for a while, so another decision is needed. The Centaur is great but ofc sucks against medium tanks. The Cromwell is solid but excels at nothing and the Firefly sucks if your opponents kept his infantry alive throughout the game and is using them well.
Team games are another thing tho. Especially if you have USF players saving your ass early while you reward them with awesome global Commander abilities and maybe emplacements in the late game. Churchills will be nerfed, it's ok.
Last Thoughts
Is there anything positive about the faction? Of course. Everything not mentioned here. The Commanders are nice, the tanks FEEL sweet, the sniper is useful (to some degree), the voice-over is great, the AT gun is love, the AT gun is life and the call-in units are interesting and effective. Although expensive. Ugh.
Thanks for reading. t_t Spelling mistakes are intended and meant for comic relief.
Need a tl:dr version for the drunks.
Brits have bad mainline infantry, bad Carrier as well as resource management problems (especially MP), lack light artillery options, stuff against garrisoned units, a mid game AI vehicle and mobile reinforcement options, are expensive to maintain and require the most micro, their engineer unit with barbed wire and mines comes much later than with any other faction and their overall game pacing is problematic