Scribe
Legend
I'm also not a fan of tiers; I'd rather the progression from any one level to the next be roughly the same in terms of power-ability-etc. gain when averaged across the classes.
Thats what I'm suggesting, but you still have those points (6, 11, 16) where what you knew/where, changes. This is a staple of fantasy really, and power progression in many genres and types of media.
While yes we can have 5, 10, 20 levels of the 'same thing' but the numbers go up, I think that there is room for something else which tries to cover more of the actual played (D&D) landscape of the modern game.