The thing about Wade other than stats because he had GREAT stats is athleticism, same with Garnett, with Bryant, with Stoudemire, McGrady, James, Jefferson, Iguodala, B Davis, Iverson, Marion,
etc.
Okay outside of Marion, they all had POINT skills at their respective positions, size, and solid all-around stats, etc. Most athletes have the chance to become a defender...
A Prospect with top-tier athleticism, size, all-around game, and POINT ability is more than likely going to be pretty good - not all will be stars, but with the Point ability, they can make others better while having athleticism (crucial) and all-aorund game...
IMO all these were easy to tell, that they would be good... Stoudemire wasn't a great passer stat-wise but in the All-star games you could some passing ability.
Marion didn't really have great passing ability but at 6'7 the guy averaged like 1.8 BLKs in College while putting up great stats in all other areas (minus 3PT) - almost exact same numbers, he's putting up now.
Gerald Green IMO was harder to scout, because I only saw 1 game and I didn't get to see rebounding skills, Point skills, ball-handling, steals, blocks, etc. and I really didn't get to see overall game. I don't recall seeing stats, to see if he has an all-around game either - REB, AST, STL, BLK, etc. but he is an athlete, that's for sure.
Garnett, Bryant, Odom, James, etc. those players in H.S all showed an all-around game. Stoudemire showed the fire, he plays with now... I never got to see McGrady in H.S McDonalds game but he was rated higher than Odom and Odom impressed ME a lot in H.S before going to College...