But... Marco Van Basten WAS world class!
Are you on about longevity? Being at a level for x amount of time?
For John Stones only injury stops him being touted as so. The talent, otherwise, is absolutely there.
He has pace, power, timing, reading of the game, skill out of defence and the eye for a progressive pass. He's not just a hoof merchant defender as he can also play as a DM as we've seen.
All this has improved with age so, essentially, he has put this all together in the last couple of years. Not sure who else, on the main stage, has that much more of a skill set.
For me comfortably world top ten, outside of injury, defo European top five and maybe top five in the professional world game.
That's just me though.