I don't think there is any legit reason for Sampson not to recommit to SJU. He'll start right away, and based on early results, the program has taken a quantum leap forward. All the reasons he chose SJU are still in place sans Lavin (which cannot be dismissed). He can't help but be impressed with Mullin, Matt A. and Slice and the fact that those two assistants bolted top programs to work with Chris at SJU.
Just a crazy hunch, but with Matt A. and Slice already recruiting Diallo, SJU now has important recruiters from 2 of the 4 other schools on his list. Stands to reason that if these top rated assistants chose to leave those schools to come to the bright lights of NYC, then Diallo pays attention to that as a big positive. I think Sampson falls first for SJU, and gut feeling is that all the positive inertia causes Diallo to go this way also. If anyone can convince Diallo that SJU is a better place for him, it would be Slice.