The interesting evolution of Ninjago's animation and visual quality

Let me explain myself: The pilots released in 2011, produced by Wil Film, and it had a pretty decent animation and quality specially for a 3D animated series on 2011 standarts, though its clearly experimental and some movements look stiff sometimes. then we got S1 - S2, which improved a little bit but overall it remained pretty consistent from the pilots, maybe some better quality here and there. but one thing that stands out even since the pilots, are how different the characters are...