Subtle changes, bugs and feedback

This has two problems:

1. A loss of privacy. One of the biggest reasons people requested name changes is because they wanted to not be found by employer/ex/family/etc. The vast majority of people user the same username everywhere, until they determine it's a risk and need to change it. We'd be permanently linking your old identifier to your new one.
   
2. As sign-in is via email (because you can change your username), they need a whole new email account just to get a new username.
   
   

The current situation is the best for privacy, and security.

But if people feel that this has eroded trust, as people could change their name and you cannot see the history of who they were and carry trust forward... then I can fix that, but it comes at the cost of some privacy.