Embiid's question marks: limited time playing high level basketball, age (he's older than Parker/Wiggins he's a month younger than Nerlens Noel), and his back.
I think you hit the major 3, but he also isn't exactly dominating college players, is only playing 23 minutes a night, isn't a superb rebounder (for his size and being in college), doesn't have much in the way of post moves, etc.
That (the bold part) is just wrong.
Embiid is pulling down 13.5 rebounds per 40, pace-adjusted.
That is dominant rebounding in college.
For comparison, Anthony Davis averaged 12.9. Greg Oden, in one of the more dominant college 'big man' seasons in recent times, averaged 13.6. Sullinger averaged 13.4 his freshman season, then 11.9 his sophomore season.
So, basically, that's the level of rebounding talent we are looking at with Embiid.
The only 'question mark' I can see with Embiid are whether his back issue is just a strain or something more chronic. Hopefully Danny will know more than we do by draft day, should any such opportunity as this thread is discussing arise.
His age doesn't bother me.
I'm also not worried about the 'only 24 minutes per game'. He's on an extemely strong roster that doesn't need him to play a ton of minutes in each game. Wiggins is the _only_ player on that roster playing over 30 mpg. This is college - only 40 minutes in a game anyway. Embiid has played between 25-33 minutes in half of his games, with most of those coming in the second half of the season.