This is silly here, and would lead to huge abuses. One game that does this sort of thing decently is DDO, you can reincarnate, starting over from level 1, with certain bonuses depending on your previous class/classes, and each time the amount of xp needed to level goes up quite a bit. Here, since you can just swap jobs, it would just lead to people maxing that class over and over until they couldn't get the bonus anymore, and can you imagine the groups that would kick or leave if you didn't have those.