Would say Foden Hudson Odoi and Sancho are all potentially world class, some of the best talents in Europe let alone England, for comparison I don’t think we have a single talent in their age groups at that level, maybe Jones and Brewster at a stretch, but these guys are elite.
I think people's definitions of "world class" is where debates start about this topic.
Also an incomplete ability to assess a player according to what is needed in the professional game.
There are four (or five for some people) areas that players are to be assessed by - Technical, Tactical, Physical, Psychological (or psycho-social, depending on your ideal).
When you assess from those four criteria, you can start to see why the truly "world class" players are "world class". They score highly in all four pillars. Not just highly, but very highly, almost near-perfect in every one.
For me, Foden maybe lacks in the physical department to be truly world class as a midfielder. If he develops his strength, that might change things. But we haven't got enough minutes to judge him on at this level for the other parts, so it's too early to say. But I don't think he has ALL the attributes to be world class. But then again, my interpretation of "class" is quite strict
World Class - would start every game in every team on the planet
Top class - would start every game for most teams, but would be in and out of the first team for the absolute best teams in the world
Good - what it says on the tin. Capable of standing out in certain teams, but wouldn't get on the bench for the absolute top teams
Average - lower league players, generally get by on being physical and abundant in one specific skill of the game (heading, crossing, shooting, dribbling, etc)
Bad - players who, more often than not, reached the professional level due to an abundance of athleticism and not much else. Severely lacking in tactics and technique, and also psychology
Paul Konchesky - players who won a raffle to play pro football (e.g., Paul Konchesky)