If people are worried about names that are stuck on alts that people aren't playing, or people preserving names, the PTB could just wipe the server of unused characters to free up names like the Devs use to. Same guidelines. Accounts that have been inactive for X amount of time. (Years, not months or so. If we EVER get to that point.)
There is also the possibility of more shards opening up where the name you want isn't registered.
These are just alternatives in case everyone is a stickler for One Name Per Server rule.
Personally, I don't mind linking the names to the global and allowing people to share similar names. I can't recall ever running into someone with the same name on Champions. Not even the names of my alts. And I have some pretty unoriginal names.
I should mention that the reason why I'm for name sharing is because we have fewer servers than we did when the game was under the rule of NCSoft, so there is a statistical likelihood of people missing their names.
Hopefully that'll change as time goes on.