Possibly unpopular opinion: Robert Williams is a good offensive big man, but a poor defensive big man. He keeps the ball moving, sets good picks, swings it side to side, finds the open man, and is a real threat on rolls. From what I saw last night, he was in the right position defensively about 25% of the time. He made a few nice blocks and recoveries after a pick-and-roll, but he was consistently out of position and made little attempt to hedge off drives to the rim -- that was against G-leaguers. He has to get better there. If he hedged the lane half as well as Theis, he would be a starter for a long time in the league. Theis is only in the NBA because he understands positioning so well. I think Williams will get better, but I'm guessing he's gonna need 3-4 more years before he is consistent enough to be relied on.
I like Romeo too. He's doing the little things really well right now. One thing that bothers me is that he is not getting enough touches to create on offense. Maybe it's a rookie thing. Maybe he's a bit passive. That's his best skill and I look forward to seeing more of it.