You can choose the amount of players divided to classes like this:
sol/eng/med/fop/cop -------- 100%
And then you divide them. This would prevent the over-use of some special classes (mainly field and covert operations). And then you could see a huge amount of basic soldiers and just afew specialists. Currently the teams are very odd: 0sol/1eng/2med/3fop/4cop And with this idea we could get 4sol/2eng/2med/1fop/1cop which would somewhat more realistic.
Also there should be an option to balanced teams:
axis% and allies%
This could be especially fun in the battery map. (something like 40% axis 60% allies.)
What do you think???

