On offense, his ability to get to the rim is impressive and he's an adept finisher once he's there. On defense, his on-ball defense (positioning, timing, etc.) seems to be advanced.
Those skills can quickly translate to the NBA level if he has a great work ethic to know his role in Brad's system. I can see Romeo being great in Hayward's role (dribble-drives, catching the ball on the move, etc.)
Hopefully, he develops quickly because he's going to be worth much more than "insert random big".