BlackMesaSouth has the right idea. I already play medic quite a bit, so I'm sure I'll be thrown into the group of people rushing to get the unlocks. It can't take more than a week to get the first unlock, and then the long arduous climb will begin. Some of those achievements are quite random and intense, so I think the rush will blow over quite quickly. The Goldrush-rush will hopefully not blow over as fast =P
People will initially leap for the achievements. You can't blame them. But it ruins the equilibrium of the game. However, as time passes, the game will reach equilibrium once again.