You might simply want to give the players a chance to re-do the characters. Obviously you would want them to stick with stuff that had made for important RP points, but a chance to rework the characters now that they know what they really want to be doing with them and now that they have a better idea what works. Would likely improve the effectiveness of everyone significantly. If it's been two years, then enough stuff has come out and enough stuff has changed (like the creation of the MT class), that it would straighten out the kinks.