Let's take skins to the next level, eh?
Let's add in voices that fit the champion for the new skin they receive. For example, if a champion is going to receive a skin that makes him/her more menacing, give him/her the voice to act the part, apart from his/her original, friendly skin (and vice versa, if a champion were to receive a skin that makes him/her more friendly, apart from his/her original, menacing skin).
This would make playing the champion with the new skin so much more enjoyable. Riot, you're bathing in cash. What's stopping you from getting the voice actor of the champion to come in and give a few new lines?
I understand that some people are going to think, "But isn't that basically taking the skin one step further to becoming a legendary or ultimate skin?" Well, depending on how much RP the skin would cost, if Riot decides to go through with this, it may be, indeed, one step closer. But looking at it from the real perspective, a skin is supposed to change a champion. A champion is not changed if something is left behind (the voice or what he/she says and how).
Riot, please spice up the skin game in League of Legends. Trust me, from a business point of view, you will be bathing in more money than you are now. From a true gamer's perspective, he/she will truly enjoy the game more than they do now.