Okay, so from what Rilla said, they were quite prestigious things. They had a uniform rule, maybe? Based on these tournaments more than likely. 

Well, right away you alienate Rpers with that kind of fluff. Rules, mechanics - YUCK.

Should come down to two mature players, facing off their characters in a Colosseum in a freeform manner. The GM would be the referee. Simple right? 

Bottom line though, from my humble opinion, is that everyone LOVES FIGHTING STUFF. They do, they really do. Arena should be what it is advertised as: battle-centered. That don't mean half of what most people prolly think it means.

Maybe I'll take a crack at it. I think I know what's gone wrong, although I could be talking out of my bum and then some.