Suggestions:

1. Blacklist in config for color and formatting codes that can't be used in /nick
2. Limits on how many different color and formatting codes can be used with /nick
3. Toggle if exp orbs drop or if experience goes straight to the player.

1 and 2 just seem unnecessary.
3 seems like the job of another plugin.

Okay, but for 1 it would block players being able to add colors like black that would be hard to see in chat, and dark red which is often associated with admins.

...actually closing this time.

Related PR for 1: #1441
Closing as 2 and 3 are unlikely to get implemented and 1 is a duplicate of #187.