I think its fine to make generic "warring kingdoms" skins but don't attribute a character to something and have zero qualities or distinguishing appearances shared between them. What similarities does Kat or this skin have with Diao Chan? Historically or from Romance of the Three Kingdoms. I'm sure the Chinese market and Tencent want something diao chan-esque and I'm sure it'll sell like hot cakes but I don't understand why you didn't use a champ who could actually portray the novel character(Sona, most likely) or that you didn't choose an equally popular character(Sun Shang Xiang) as the basis for the skin. The whole thing seems like tencent sent you a letter that said "Diao Chan skin pls" and someone was like, "I know I heard of Diao Chan before".
TL;DR: I know what the Skin team is capable of. I know these skins are incredibly popular. This particular skin seems half-assed.