Two resonably major changes have been announced by Tom "Kalgan" Chilton, WoW lead designer in charge of balance, in a forum thread.
First, a change is planned to be implemented to prevent you from changing gear (besides what's normally swappable during combat, i.e. things that occupy the main hand, off hand, and ranged slots) during an Arena battle:
We do plan to disallow gear swapping (other than items you can normally change while in combat) once an arena battle has begun.
Ands secondly, something that has previously been the subject of much debate, with proponents on both sides of the fence. I think it's safe to say that it's the bigger of the two changes: DoTs will be affected by resilience. When asked "How about making DoTs affected by resilience sometime in the near future," Kalgan replied:
That's going to happen too.