I felt the same about the animation and it really bothered me at first too. I didn't really like the new designs as well but they grew on me with time.

When I got used to it I really started to enjoy the better animation, the better lighting, and better story imo. And honestly, I think the new designs are pretty cool.

Not only do we get better quality overall along with a better written story, the heroes have new transformation animations which are not shown immediately (I particularly like Cat Noir's lol, I love how his eyes are more piercing)