The characters have 0 resemblance to their originals - neither in appearance (which would still manageable), nor by the personalities ago (absolute no-go!). It will not even complied with the simplest requirements of the series (example: firebenders need a fire source - without this they can not tame Who knows the original knows that the sun is the fire source itself and one that can operate even in the night. ).
And why is M. Night Shyamalan has decided to occupy all firebenders with Arabs, South and East Asians? I will light there was not one of the meaning behind.
For 3D effect I can not say much because it was not available. If my film might as well watch in 2D, would not all made to a big difference.
Further, absolute point of criticism: The scene in prison .. Ok. Came in the series also. But why it takes 6 adult men to curb a pebble (Consider: The template can even stop the inexperienced earthbenders rock / move)? And why go the guards in front of this stone in coverage? Would hardly get a dent in the armor.
All in all, the film has not even really have a star. Poor animation, bad writer, director and even catastrophic catastrophic occupation. Pity about the template.