Adopting the MLB Draft rule would be an excellent upgrade.
As for the high school busts…the data would say that’s a bit overstated.
From 95 until they stopped in 2005, 23 High School players were taken using one of the first 20 picks in a draft. Of those, 9 have made NBA All-Star teams and All-NBA teams.
And for those taken in the lottery (top 13 IIRC), 8 All-NBA players and nearly all the rest have played at least 500 NBA games.
The All-NBA guys in the top 20 are Lebron, Dwight Howard, Tyson Chandler, Kevin Garnett, Tracy McGrady, Amare Stoudemire, Kobe, Andrew Bynum, and Jermaine O’Neal.