How come there aren't more Chroma Packs/Skins?

I just saw a custom Chroma Pack for the Blood moon Yasuo skin and it looked AMAZING. Just recoloring it green, blue, or even purple looked beautiful. This is just one example of a skin that could do with a Chroma, but this raises the question, how come there aren't more Chroma Packs/Skins? I wouldn't think that they would be all that difficult to make but I could be wrong. I just feel there should be more Chroma Packs and if it takes awhile for them to come out then maybe RIOT could implement a community voting system for which Chroma Pack to be released next. Just an idea but if a dev is reading this, it would be a small difference that would give a much better impact on the game for me and for many others.

Edit: Sorry I forgot in original post but this is the link to the video of the yasuo custom skins https://www.youtube.com/watch?v=C7RMnA86JoM&t