I've been using the nick 'brk' for maybe 20 years, but I still frequently come across random places where it has already been taken.

So, you'd need a nick registry, like domain names, and you'd run into issues with your friends that have "common" nicks having to register and use a different name. I think this merely trades one well-known set of limitations for a much different and less understood set of limitations without actually truly solving anything.