Simmons at center is a terrible idea. I think he could probably play PF against most teams, but he shouldn't be center ever. He can't take the abuse to his frame. I also don't like Durant at PF. The Nets have talent, but really do have a roster construction issue. I think ideally they'd have Simmons at PG, Irving at SG, and Durant at SF. Now maybe they can get Harris out there, but they definitely need an upgrade at center.
Looking around the league at players that might be available that would seemingly make sense for them, I think they should try to get Love from the Cavs. Maybe something like Harris and O'Neale for Love and Wade
The Cavs get a mega shooter at SF, while the Nets pick up the shooting and rebounding big that makes better sense on the roster and they basically just swap back-up PF's.
So if the Nets did that they'd be
C - Love, Claxton, Sharpe
PF - Warren, Wade
SF - Durant, Duke
SG - Irving, Curry, Thomas, Edwards
PG - Simmons, Mills
While the Cavs would be
C - Allen, Brown
PF - Mobley, Markannen, O'Neale
SF - Harris, Osman, Okoro
SG - Sexton, LeVert, Windler
PG - Garland, Frazier, Rubio