Why does Sultan Tryndamere have the best animation out of all of his other skins?

Just...why? When you compare all the skins together, in terms of animation, Sultan has the best. His animations are fairly smooth when you look at it. Meanwhile, 4 whole skins (WK, Nightmare, Beast Hunter, Chemtech) released after this, which are more expensive with acception from Beast Hunter, still use his base animations and looks horrible. Hell, that goes up to 5 since his Legendary practically has the near same animation.

I know Tryndamere is an old champ, I know people will say he needs a rework/update, yes, but the fact and proof that any new skins that Tryndamere will get in the future is just annoying to me when one of his cheaper skins has the better animation than all of his other skins. Wouldn't it make more sense to have his future skins try and have improved animations put into them if we're getting 975+ RP skins for the guy?