I'd say that for a player to be considered World Class they have to be at least a certainty to make the subs bench of a World X1 team, so obv quite a few named itt don't fit that criteria.
It's a shame that Sir Alex doesn't see fit to give credit to players he's falling out with that obv do fall into this category, never knew him and Schmeichel had fallen out ? He would surely be a lock for the whole football world, definite Goat contender for GKs so that's nonsense.
Of the four he did name is Ryan Giggs World Class ? By my above definition that is. He's obv a great player, and what he's achieved is insane, but I'm not sure he would ever have made the team, if you think yes then when would he have got on the bench of a World X1, no way he's ever starting that's for sure. The other three are for me as well as him with the silly name above and Roy Keane also.
So we're only having 2 world class keepers per generation?