The thing is, you can't really play Vando with Kessler. You swap him for Collins you can comfortably start Kessler, have serious size, and move Olynyk to 4th or 5th big ciming off the bench, where he is supposed to live. You can now move further away fro Gay as well as you have enough offensive punch.
Additionally, by moving Beasley, you open up playing time for NAW and Abajji. One of them is going away when Sexton comes back, which would be a damn shame. I love Beasley, but I like the idea of seeing what Abaji and NAW REALLY have before the draft.