We shouldn't bother, since it will get playtested well enough by just having it in a general arena match. It will get paired with other avatar classes, druids, incarnates, monks, and other homebrewed classes. In the span of one month, it will have (just the water bender even) over 10 matches against official material under its belt if everything goes smoothly.
Also note this: no homebrew will be accepted until it has been reviewed and deemed fit for combat. We refs (me, Prime32, AfterCrescent, and Tshern) will pair characters up against similarly powered characters as best we can, so power levels won't vary (well, shouldn't) until later matches in the round.
All we need you to do is make a character (or up to 6) to play in the arena, and when we have 8 different players of the same level: we'll create the round. With 6 characters allowed per participant at a time, we can have 6 different tournaments going on at once with only 8 players, provided they all make 6 characters. That's 24 games to start with. 84 matches with those 6 rounds, and 48 characters. That's only with 48 characters. The GitP arena has many more than just 8 people with 6 characters each. I have a feeling that once we get the word out there it will grow rapidly to rival the GitP arena in size (which this arena is based on). Point is, it'll get both enough screen time and standard opponents. Not to mention the fact that any class, feat, item, or anything else allowed into the arena will be pretty well balanced going into it. This is just that final measure.