so vi, lucian, quinn, garen(like he really needed a skin) gankplank, and azir get new skins

What if they'd made lunar revel yorick? That would have been awesome.

As for the champs you mentioned, most have only been out about half a year. There are a lot of other champs that need skins first. Yorick is the exception, though, as he's been around for 6 years and only has two skins.