Well, a large number of the feats homebrewed for the class would make good additions to a Hunter Ranger build, but I don't think the class as a whole would apply to the Avatar setting as we've built it. Of course, any player could ask for DM approval to play it anyway, and it shouldn't be a problem.
Now, I've gotten an idea in regards to the ranger. What if we traded out two or three of the Favored Enemies in exchange for Favored Environment? I've always thought that specializing in an environment fit the ranger's flavor much better, but was nowhere near as useful in combat. My current idea is to switch move the first level Favored Enemy to second level, and put a favored environment at first level; then allow a player to choose whether to specialize in a single enemy, environment, or branch out in either direction for the rest of his levels. Thoughts on this?