If Klay's healthy, GSW trading for Simmons is being heavily considered. Adding him gives them a team with elite speed, length, passing, ballhandling, and defense, if they bring in a 3 and D SF/SG to replace Wiggins.
Offensive spacing is important, but it's not the most important factor in winning, not when you have Curry/Thompson and a potential top 5 defense. The Warriors won 54% of their games without Klay while pairing Green, Wiseman, Looney, and Oubre all shooting sub 32% from 3. They'd have the versatility and depth to play at whichever pace they prefer on both ends, elite in transition and defensively in the half court.
Value-wise, a package of Wiggins, Wiseman, 1-2 2021 lottery 1sts is going to be tough to top in a bidding war. The trade would be contingent on a 3rd/4th team to flip Wiseman and the 1sts to because the Sixers are going all in on a Championship and those pieces are not ready.