It is client side -- The interface itself is still Serverside, so it has additional checks where it shouldn't which is what causes a problem with positioning, because you can properly position yourself but if you do so before the server check, it will still treat you as if you didn't move.
So what would solve the problem, is giving the client complete control of the game aside the usual server based data (stats etc so you can't modify it like some games.) XI and FMO was pretty much client dependant, XIV's initial design was to try to stop RMT before it began.
