Personally, while the Chinese skins do look good, I do not think some of them fit the aesthetic that League of Legends has with their character art. For example, if you go to the store, look at the row with Galio with the ones above and below him. Galio's art stands out as different, too detailed and uses lighting completely differently (even compared to some of the newer champions). It looks like two screenshots from different games. While if you look at his current art, it follows the scheme that League of Legends uses, and I did not mind it that much. Some of the other ones changed, Alistar and Fiddlesticks, were in need of new artwork. I do approve of the Fiddlesticks art more than Alistar's though.
Malzahar I was on the fence about. I do adore his Chinese art, but did it really need to be changed from his old? It did follow the aesthetic as well, but time will tell.
As for the skins that are being changed, I am okay with most of them (with thumbs up for the new White Mage Veigar), but as others had mentioned, Bird of Prey Anivia does lose that sense of "I'm a bald eagle! SQUAK!" with the Chinese art. It's harder to tell, and a bit less majestic in this action pose.
As for the other champions and skins that might need a touch up (Blitzcrank, Malphite, Mundo, Amumu, Nunu, etc), I do hope you look at the art that came recently before coming to the conclusion to jump straight to the Chinese art. If it looks like it will fit, go with it, but from looking at what you have done with the earlier champions, namely Veigar, Ashe, Tryndamere, Gangplank, Taric, Morgana, and the others who got an update, I absolutely love the work that was done with the new portraits, and hope to see a similar caliber with those that will have their art redone, as well as those champions who have yet to be seen.