I agree with the Skrall part.
They just looked like bunch of screeching debilitated Vorox...and Tuma simply looked like he was there to look brute and übber and seemed like a dumb giant in the end.
On the other hand I really enjoyed Click, those little moments where he nods or is part of a debate are really cute.
I also think they did a really good job on Berix, I really enjoyed his character. I was also surprised how many action scenes are in the movie, it´s hard to get bored with all the greatly animated battles and moves. The story and characters are well written and I don´t believe I found any story flaws (except for AM having other land on it and not beiing able to se MN robot from space, since he is in the space from his waist up and of course Ignika´s trajectory is somehow messed up in the beginning).
The animation, like I said is excellent (except for one Skrall in the end running but not moving), rusted and dirty textures make the characters look more real, which is a good thing and the voice acting was great and the voices themselves fit their characters very well.
I really enjoyed the movie, they´ve done a superb job.
Can´t wait to buy the DVD.