One thing that I thought of:
Avatarland is in a really crappy section of AK. Meaning, if it's not something that is going to draw you to it because you seek it out, which I doubt will be a problem in the first few months or years for it just out of curiosity, it'll be forgotten.
Think about all the times you passed by the path to Camp Minnie Mickey without a second thought or even wondering, "What's back there?"
That problem doesn't have anything to do with Avatar, it's just a "dead space" problem parks can get. Places inside parks where people rarely venture. I think the Wonders of Life Pavilion suffered from it at Epcot and the Living Seas also suffers from it.
I remember Drachen Fire at Busch Gardens Williamsburg. A buddy and I went to ride it soon after it opened. I knew the park layout as I used to live somewhat close to the park and would often visit it. We were seeking out Drachen Fire and, oddly, we had to "find" it. It wasn't anything obvious but kind of weirdly tucked away in a seldom used corner. Both of us thought it was a really odd placement.
Whether it were Avatarland or the original Beastly Kingdom area, I think the same problem would exist. If anything Avatarland will likely have a greater draw so it, in my head, is less likely to suffer from it. Still, I think it's a problem.