Timing is terrible, as we are just about to get a new mod, but I've been thinking about it, so I thought I'd contribute...
I have been feeling that there needs to be something constructive for capped players to do. Crafting was a great addition, and does create an objective players can go after even after they are capped. However I can't help but feel that anytime I run a capped character I am wasting time and energy that could be spent on leveling other guys. (I have 3 accounts, so I have lots of guys.) Yes, I realize this a weird neurosis, but I don't think I am the only one who has it.
Soooo what I would *love* to see would be a system that translated post-cap XP into something useful. Other types of goods, or account specific benefits, or guild benefits, or familiars/minions/etc.
Just a thought.