Hook : I've looked at this again, and it's not as silly as I/we first thought.
If you make a random OOB, it only takes a few seconds to go into the OOB and change your Corps Commanders with the click of a button, now the question :
Why would you field an Army with poor grade CC's ?.....no one is going to do that when it takes 60 seconds to change them all to good or very good ones. I don't see this as a "cheat" but pure common sense, it would be crazy to have 6 poor grade CC when it's so easy to "swap" them for better ones.
This is a vital part of the game, the CCs do make a big difference. You called it gamey and I understand what you mean, but a big part of the enjoyment in PBEM and MP is going to be buiding you OOB for each different battle / map / opponent. I could not expect anyone I was fighting a battle against to NOT do this, after checking how easy it is.
Now, if everyone does the same, then there is no problem becasue it's the same for all - you pick your Commanders as you pick how many Cav or Arty you want the army to have, it's a great feature, but.......it's like saying the OG cost the same as the Line Inf !.
As these guys are very important, It would make sense to have the better Commanders "cost" more than the worst ones - don't you think ?. OR, a limit on them, so you can not have all the best ones selected, like you have a limit to how many OG you can field.