Am surprised this (according to Search) hasn’t been suggested before, but as the game dips its toe into less PvP-focused game-play, it could be an opportunity to update character leveling too?
Roleplay board/table-game like AD&D, Rolemaster, et al have always used a wider set of Attributes/Skills when leveling up. This makes each character more unique. Currently characters are pretty much the same by the time they are max level.
Basically: expand Attributes and Feats.
Having some expanded-Feats increasing because the player uses some skills more often than others. For example, since the way the Attributes are pretty wide reaching, on leveling up, a player that uses the bow successfully more often, gets a point or three to that in addition to the standard leveling points. Using a mount more than running about gives some added benefit when using mounts of that type.
I doubt the overhead to game play would be massively affected by including these added tracking stats. I am also sure others can think of ways of expanding the current leveling?