So I've been searching around different r/mains and I've noticed something about a few champs

A few champs seem to have skins that actually make them feel clunky.

For Darius (I have a lot of experience on this guy), his dunkmaster skin seems incredibly clunky. His W resets don't feel or seem anywhere near as fast as W resets on his other skins. His Q always seems to miss when it should hit and vice versa.

For Jayce, it seems to be his forsaken skin, and I can see why. It looks like everything is in slow motion when using that skin. I used his base skin and then watched PKB Dovah use the forsaken Jayce in this video, https://www.youtube.com/watch?v=JGx64-aeOLM&feature=youtu.be&t=6m38s and he just seemed absolutely disgusted at the skin not because of the aesthetics, but because of the skin feeling clunky.

Can a rioter confirm the clunkiness? Is it just perception? Is it actually a problem with that specific skin? Should the animations be sped up or otherwise fine tuned? I've long stopped using dunkmaster darius in ranked because I feel like I gimp myself whenever I do use that skin.