Have you ever considered trading xp for items?
I know it will cause more grinders to appear but this idea can also double or triple the time for exping and people would have much more goals to accomplish = more fun.
The idea is an NPC with services for epic lvl characters like:
-trading experience points for essences which can be traded for special items like ring of regeneration, ring with elemental dmg reductions, bags with 100% weight reduction etc.
-trading essences for scrolls of time stop, GS and true strike (so the builds like 20fighter/7wm/3rog or bard/bg/fighter will have to think twice before using those in pvp)
-relvl (takes all xp from you and gives you half back so you can alter the wrong feats etc.)
IC it could be a Ilithyd who sucks your experience in exchange for epic items etc.
You could also use it to improve barbarians who are ridiculously weak in comparison with fighters since they got the +1echant/5lvl - like making special items for them etc.
edit: I wrote barbarians and rangers... sorry about that I did not know about the improved companions
