@AD2001 good points thanks for your post :) , but I'm ok with that differences, these give each faction a bit of personality. What happens is that there is a lack of vehicle roles in each faction, and that is what is unbalancing things.
for example:
Attack helicopters: NATO has the AH-99 Blackfoot, and CSAT have Mi-48 Kajman , sure they might be different form each other, but they have a vehicle that fulfills that role. my question is, where is the AFF Attack helicopter? I suppose devs are going to add it in a future patch, but in case they did not consider it, here is the request to let them remember. (Maybe eurocopter tiger?)
About the Light transport/attack helis and Medium transport helis, I think it is balanced as it is right now, although NATO ones are more specialized for each role:
NATO has AH-9 Pawnee, which cannot transport troops, but can give light/medium air support. Then the MH-9 hummingbird has no weapons, but can transport some troops. Then NATO also have the UH-80 ghost which has 2 miniguns at the sides, and it is able to transport more troops than the MH-9 hummingbird.
CSAT PO-30 and AFF WY-55 Hellcat are a mixture of the AH-9 Pawnee attack capabilities and the MH-9 hummingbird/UH-80 Ghost transport capabilities. Despite that, I would like to se a MH-9 hummingbird kind of aircraft for CSAT and AFF, so at least this way they would have more than 1 transport and recon helis.
''MBTs - They both have a 120 mm cannon, but the NATO one can carry 6 people in the back, while the CSAT one is smaller and more agile (or is it?).''
Not sure about that, I don't remember either the AFF tank characteristics, the MBT52 Kuma. also there is a new version of the NATO tank.
''Heavy transport helicopters - Only AAF has them (at the moment?).''
I hope is only at the moment as you say, I would like to see the return of the MV-22 osprey as a NATO heavy transport helicopter, not sure about what the CSAt could have. Any ideas?
''Jets - Only AAF has them, at the moment.''
Check the last Arma 3 update, 2 CAS aircrafts have been added:
A-164 Wipeout (futuristic A-10 )
To-199 Neophron (Reminds me of the su25 frogfoot)
I think they should add 3 more that were specialized in dogfighting though. (CAS/AA)
AA and arty vehicles - Okay, they're completely the same, just mounted on a different chassis. NATO does have an MLRS, though.
Well that's unbalanced too:
Artillery:
OTAN: M4 Scorcher
CSAT: 2S9 Sochor
AFF: NONE
MLRS:
OTAN: M5 Sandstorm MLRS
CSAT: NONE
AFF: NONE
AA vehicles:
OTAN: IFV-6a Cheetah AA
CSAT: ZSU-39 Tigris AA
AFF: NONE
the other thing I missed a lot in this game are the cargo transports such as the C-130, there aren't any cargo transport to deliver supplies yet. That's why I suggested the V-44 Pelican for OTAN, I have no idea which ones could CSAT and AAF have though.
Weapons seem to be alright.