I was thinking that an interesting approach to prestige classes would be to eliminate them as they currently exist and instead make them branching options on existing core classes. Say once every three levels gained in a core class the player is presented with the option of continuing on in the core class or taking a prestige branch. A character may never go back once he's started down a branch.
Each branch could offer additional branches as it grows. This would make the core class descriptions much longer.
Each branch could offer additional branches as it grows. This would make the core class descriptions much longer.