I guess it's very good idea to change nickname more than one time.
Some people think, that it will be too hard to recover account after its loss, but I don't think so. It's not so hard to make confirmation of nickname changing by e-mail or Google (AppleID) account, and allow this feature once a year. You can track every operation of each account by ID, and check if this player is Town Hall owner if necessary.
I hope you enjoyed my idea!
Clash on!

