So lets get this straight:
British Unlocks for what you describe:
Tier Upgrade which requires nobody present at base is...
30 fuel 180 manpower = Tier 1
10 fuel 100 manpower = Grenades
15 fuel 150 manpower = Guns (on any squad not just grenadiers)
35 fuel 150 manpower = 5th man on the squad
45 munitions = 1 bren ( on any squad of your choosing )
I'm going to leave the 5th man out, because that's obviously late tier and Grens don't get access to it.
Total cost is 55 fuel and 430 manpower.
Now lets look at OST:
10 fuel 80 manpower: Tier 1, you know, so you can build more than a pio or an mg
40 fuel 100 manpower: Tier 2 research
20 fuel 200 manpower: Tier 2 building, plus send that pio home to go make it
60 munitions = 1 LMG on a grenadier only
Total cost is 70 fuel and 380 manpower
Don't forget both UKF/OST infantry love fighting in long range fights in cover. But IS can build their own cover, OST needs the pio to do that for them.
Yeah but you're ignoring the fact that sections get no snares, are absolutely terrible on the move, and the fact that 1 bren is worse than an lmg42. Brens are also pretty dependent on the cover bonus IIRC. Ost also has better team weapons and you can hardcounter brits with double mortar since they have literally no answer to that crap. Brits also have no other combat infantry than sections nondoctrinally. So it's not all as bad as you make it look.
Fixing both Pzgrens and Ostwind would most certainly help boost/solve the issues that they are facing. Pzgrens are costy, price should be decreased also due to the lack of utility. They should cost like 300 manpower at least. Also price compensation for dropping like flies. Although vet compensate later on but it takes a while.
It would be cool if Pzgrens could get flamethrower as an upgrade option AI focused, but that is just an idea. Not neccessary but would be a nice AI addition. Might be too strong an option. Maybe it is a no go.
Ostwind is underperforming, needs to be more accurate, deal more damage or have bigger AOE. Currently it feels like the worst AI vehicle there is. It relies heavily on unit support in comparison to every other AI medium tank vehicle. It needs to be improved.
Grens do not need fixing I believe, just the 2 above mentioned.
Then Osteehr will be fixed.
OKW needs to be looked over, some units being versatile and some unit underperforming. Veterancy issues, support weapons needs some adjustments I believe (adjustments meaning fixes and slight improvements). It needs to be looked over. It has some problems. I think that is what it needs.
I explained what changes should be made on Volks on https://www.coh2.org/topic/88296/revamp-volksgrenadiers-terms-of-versatility-okw. Revamp OKW seems necessary as some perform better and worse than it should.
Pzgrens at 300mp? 20mp more than riflemen and the same as penals with that kind of dps? No thanks. I think a better (more balanced) change would be bringing their reinforce cost down to like 32, same as rangers. That makes a lot more sense to me and would help ostheer players keep their pzgrens on the field but wouldn't make them as easy/attractive to spam as being 300mp would.
Ostwind definitely needs some buffs. I would say scatter would be the best option (that would make it more accurate against infantry) since it would make the ostwind a lot more reliable without making it absolutely rape infantry hopefully.