This is a really good idea, and you are right its not hard to implement! it does mean that we wont have the dancing colours on each beat though, i will have to try to see if it looks good. Thank you for the suggestion!
Cool, would love to get notified when it's there.
We've implemented it in the full version of the game! Here's a preview: https://twitter.com/7thbeat/status/1088142654863372289. The full game will be out here in about a day now. Thank you for the idea!