The biggest draft what if for me of recent times, is what if the team didn't trade the 8th pick for Kyrie. Obviously the Cavs took Sexton, but I don't think Danny would have taken Sexton. The next 4 picks in order were Kevin Knox, Mikal Bridges, SGA, and Miles Bridges. Then you had Jerome Robinson before MPJ.
I probably would have taken MPJ, but I think Danny would have gone with one of the Bridges or SGA. Can you imagine if SGA was drafted by Boston in 2018? So instead of wasting 2 years on Kyrie we would have let IT4 retire here, still had Crowder, and ended up with SGA. Rozier probably stays as well. So the team could have been trotting out SGA, Hayward, Brown, Tatum, Horford with Rozier, Smart, Crowder, Morris, Theis, Baynes, Rob. And without Irving on the court, perhaps Hayward never gets injured. That team would have won several titles.