Username Changes
I personally think this should be also prioritized by Theymos. Why? I'm pretty sure some people here did a bad move in the past by using a username that is either:
Somewhat related to their real name
The same username as their other usernames on other websites
And what happens when people change their name here to try hide their 'crimes' or wrongdoing (either here or elsewhere)?
Which is a huge risk, as people can get doxxed easily. Similar to what happened to Hhampuz(if I remember correctly, not sure if it was him).
People should be careful with what information they put online and we can't be responsible for this. If someone is lazy with their personal info then that's something they are responsible for and need to protect themselves.
How to stop shady people from hiding using name changes
Put a name change history on people's profiles. Yes, people here on bitcointalk can see your previous usernames on your profile(probably make it so that only members and up can see them?).
If your info is online then someone can find it and implementing name changes (that are even logged) isn't going to stop anything. People could just create an external site that logs all name changes and that shows up on google. This seems like a feature that will just be abused by the nefarious more than will actually save innocent people, and again, people should just learn to be much more careful with their personal info because once it's out there it's likely not going to go away regardless of whether we let people change their name here.