When you change your display name it would be nice if it was changed in any comments mentioning you.
For instance, if someone replied to you in a comment:
@Trufa This is a comment reply
The @Trufa
should be changed to @new_name
I'm aware of some of the complications of what that might bring!
I think that it only considers the first word so, in more that one-word-names:
@Trufa XXX This is a comment reply
The change would apply wrongly (in a change like Trufa XXX => new_name):
@new_name XXX This is a comment reply
I have no idea programmatically how complex this is (or impossible by design), so I just wanted to put it out there.
I think the proposal (isolated from fact of how complex it would be) is "good in spirit", it's up to you to decide if it is a good idea.