The problem is classes should be designed around game mechanics then have flavor added onto the abilities after you have a working skeleton to flush them out. Mechs and automatons are terrible for multiplayer games. WoW added a single second health bar to the game in wrath with the mammoth mount and it was considered so utterly op that it was removed from the non combat mount...
If you take away the mech and take away the robots and focus more on gun play, grenades and maybe a few other contraptions it has some potential.