There shouldn't be any complaints as long as you don't take things away from some classes to balance things out. Just add some skills and functionality to the weaker classes.
If you need someone to make a new skill or something, I might be able to help once summer rolls around. I've only done a few simple mods to date though. I've done a resupply combo, a weapon of regeneration, and an artifact that combos all shock cores within a certain radius of you.
I don't know if this is a good idea, but you could add skills that give AMs and WMs special weapons similar to the medics. The AM would get a gun capable of filling other people's adrenaline, and the WM would get a gun capable of buffing people's damage. In theory, it would make all of the classes beneficial to each other.