World class has no boundaries or specifics so it's a load of bollocks!
There have been players in times since media coverage of football who have been the superstars: Di Stefano, Garrincha, Pele, Cruyff, Maradonna, Zidane, Ronaldo, Messi, CRonaldo.
There have also been many many others who have been superb players: Edwards, Beckenbaur, Revelino, Bell, Best, Müller, Zico, Dalglish, Platini, van Basten, Mattheus, Gasgoine, Romario, Stoichkov, Maldini, Roberto Carlos, Figo, Rivaldo, Bergkamp, Henry, Gerrard, Ronaldinho, Eto'o, Iniesta, Xavi.
In my opinion, if you're not in this class then you're not world class. We've got a lot of young players who could be mentioned with these players later in their careers after they've proved themselves for a prolongued perdiod of time. But In my opinion we have no world class players. Neither do United. Neither do Chelsea. In fact, there's probably only about four world class players in the world at the moment!