Personally I don't need real player names, because they are outdated pretty fast. And in a careermode you need new youth players to grow your squad over the years, so I guess fantasy names must be introduced anyway.
A team editor would be nice for fantasy or historic squads, like 'Hollywood actors' or 'Manchester United 1966'. Only a few people would use it to change the names to real ones or update player transfers.
If there would be an export/import feature, then the community could exchange squad rosters, without the developer risking legal issues.