I went to see the movie tonight and I can see why it didn't do well. The story was almost completely nonsensical. I'm sure 3/4's of the kids in there didn't know what they were going on about half the time. The music had nothing to do with the show but seemed to be an attempted sales tool for the music industry (way too common these days). The music was downright wretched in some places, especially the opening and there was WAY to much of it.
The rendering was good but certainly no better than the first and definitely not as good in many instances. Animators totally ignored the laws of physics for much of the swimming/underwater sequences (also far too common) which ruined that for me.
The scenery and environment were quite spectacular in most cases so the environment artists really did their job to perfection. Unfortunately it was often ruined by very long quickly rotating panoramic shots that seemed intent on making everyone sick. It's fine once in a while but not every other shot! Especially at 24 fps! Yikes.
If it wasn't for the terrible writing, obvious attempts to sell music and the bad directing this could have been quite good.
Well, there's my 2 bit review. My kids reactions was one of annoyance...and asked to leave early so that's not a good sign