Doubt unique IDs will be an issue, they have their system keeping them unique. Your actual name being original is not a big deal, it's your ID behind it that matters (despite what Sony insist with their no renaming nonsense), and that will be considered during implementation.
I don't see it really as relating to defeat for MS either. For starters, any game that implements it is levelling that particular playing field immediately. This doesn't mean Xbox exclusives on PS4 or anything, so it shouldn't really affect the choice of system to play on, either. I guess the only effect it will have in that sense is on the tiny sector of the market that buys games on both systems to play with more friends.