To be all honest, let's say it's by far not the best skin out there. Reasons, why:
1) It makes Mercy to look like Mei, as an example or just too similar to her, gives her less of a 'recognizable as character and original' look (except the wings, but that's pretty lame);
2) The details seem just not nicely thought out - what's with her boots that look similar to hooves?
3) That "feather thingy" seems out of place in the concept, sorry, Xayah vibes don't get me over there (kidding, not a reference).