@The1Rolling1Boy I guess I'll be using Saddaj, then. He's more capable in melee, but is severely weakened unless sand is present (although he can transmute both stone and brick into sand).
The ranking system is simple: you start with 1000 points. You get 100 points if you win, 50 if you draw, and none if you lose. If the match isn't ranked, no one gets points. The people with the five highest scores are shown on the the arena sub-forum, along with their total W/D/L. If you choose, you can also have your W/D/L shown underneath your avatar. You can wager points and items in a ranked match, losing them if you lose and gaining your opponent's wagers if you win. Both players have to agree on any wagers before the match starts. Certain (official only) tournaments will allow you to earn bonus points.
As for the arena itself, this could be a good idea:
(Yes, it is from Skyrim)
Plenty of space to move around, a few rocks to hide behind if necessary. Plenty of stone to transmute, and there could be an interesting scene if a fighter retreats to the mountains.