theres probably a good chance that medics will be overused to the point where neather team is losing and soldier and emgineers r losing thier minds
I'm going to go out on a limb and say that is improbable at best. Players usually tend to be more oriented towards action and heroics. While I think here on the forums there is a fairly balanced distribution of primary classes, when the game actually releases, Soldiers and Operatives are going to be everywhere, since uneducated players will (falsely) hold the opinion that being an Engineer or a Medic will be boring. I encounter this in DDO all the time: Rogues (characters that can disable traps, find secret doors, etc) and Clerics (healers) are two of the most desired party members, but simultaneously among the rarest, as they are difficult to play and don't get to be in the thick of the action.
Yes, we probably will encounter groups of players who are all Medics and constantly heal each other, but I think they will be a very small minority, since that requires a certain organization and cooperation that I believe the majority of players lack (then again, I play Halo, where going lone-wolf is a fairly decent and acceptable strategy, therefore few of the players I have encountered have any sense of teamwork whatsoever).