I don't know about anyone else but the ability to fight a bunch of minotaurs as a reward for the arena (save for the raiment) was pretty underwhelming. Personally I'd like to see -very- challenging enemies as the choices, which would also give much more gold as a reward (allowing a character to actually make a living off it and be challenged).

Basically assuming the arena (or it's replacement) works in the same rank up, rank up, rank up, grand champion style. You should have options for the battles you face as grand champion...sort of like:
(using oblivion monsters)

3 Minotaur Lords (basic) Reward- 5000
5 Altered Clannfears (intermediate- altered meaning the ones from Arkveds hall which have higher health) Reward- 8000
1-2 First gatekeeper (hard- yeah, it doesn't make too much sense for him I guess, but the difficulty is my point- and they are not weak to tears) Reward- 10000
1 Second Gatekeeper(Very hard- Again just for difficulty comparison) Reward- 20000
1 Challenger for the title(Hard- Basically an NPC that has similar stats and CE to your character, something to make him hard and show that your not the only competent fighter in Skyrim.) Reward- 12500, and 2-5 fame

The rewards and enemy types are ball parked but I thought it'd be cool if you had options, and I always have a had liking for more challenging things...
Anyway, if this has been done before or if an Arena like thing was confirmed to not be in then sorry for wasting your time, I did not know...If not, thoughts?
Oh, I play Xbox (sorry) so if there were mods for this also sorry there