well Training can be complementary to Combat , that makes it both desired and not a game breaking.
This is not to make rookie to corporal or some like that.
It may be designed to improve soldier in the current Roll it plays , i.e sniper training , Heavy training etc..
it requires the soldier to meet a cretin requirements that can be achieved during combat (medals , min score, etc.).
examples:
Sniper Course. (10 days):
requirements: accuracy 70, 10 kills, 10 missions as Sniper roll.
benefits: +10 to accuracy with sniper weapon, +5 moral.
Heavy weapon expert (10 days):
requirements: 60 accuracy , 15 missions as Heavy, Strength 65.
benefits: +5 accuracy , 1 more round fired , +5 strength.
Close combat (10 days):
requirements: 60 reflex, 10 missions as Assault, 5 kills.
benefits: +5 accuracy , +5 reflex +10 hit points.
those courses will be desired by player for there veteran troops.
It will make players use more rookies because there Aces are on training , it can create another layer of depth to the game.
I think that it may create better teams, and make a 2nd team viable
The game is probably on the final stages of QA / balancing .. so don't throw away this idea for the next expansion/MOD