This is copied from another thread but I think it's died. Anyways, is there is a reason that achievements (or at least certain categories) couldn't be unlocked from the beginning? Specifically fixin, combat, experience, and maps for engineers? Probably Flyin, Command, Teamwork, Experience, and Maps for Pilots? I'm not sure about gunning but the equivalent categories are probably suited.
A simple example is one of the engineering achievements for repairing 150 guns with a wrench. I think it's supposed to encourage experimentation with loadout but I think by level 6 you've figured it out. I tried loadouts with the wrench for a long time while I was lower level, especially while gungineering. Right now, however, I feel like trying for this achievement will let my team down. I either enjoy playing and play as a team player for the good of the match, or I play selfishly and bring questionable loadouts.
I agree at some point an engineer should be more of less forced to try a loadout of wrench, buff, ext or to learn the difference between ext and chem spray, etc. I've already done that and want credit for the experience without it costing my teammates.
In the end these achievements demonstrate experiences you've had in the game, if we've experienced them do we really need to re-experience them again in a specific order?