I don't think it matters whether we have 1,2, or 3 world class players. The Man U team of '92 season when Beckham, Scholes, the Nevilles and Butt all broke through seem to be the benchmark for what is possible but arguably only Beckham was ever world class (and alot of that was because of the hype around him). Personally i think John Stones, Ross Barkley, Romelu Lukaku have all shown that they've got what it takes to perform on any playing field in the world already - so doesn't that make them world class?
Having seen some of those upcoming youth players like Garbutt, Browning, Ledson, Dowell and Long against Krasnodar last week i think we have a pipeline that could be every bit as good as that United '92 squad went on to be. i'm not suggesting any of them are world class but there just seems to be an encouraging blend of experience and youth at the moment. Eg, Gibson and Barry get banned / injured and no fears, there's Besic and McCarthy. It's a pretty good squad all round that we have (except back-up for Howard) and fortunately they are all now getting back to full fitness so i'm pretty excited about the second half of the season.