Staff turnover can portend tumult. Boykin going to IMG seems like a lateral move at best, but more realistically a step down from Division I. Russell going back to Michigan when he came from Michigan was the most eye-opening.
Making Yianni an official assistant was the big move people wanted. Despite his notoriety, I can't see him usurping Grey due to their close relationship. Grey would need to leave on his own accord for this to happen rather than be pushed out. The new Cornell AD's relationship with the program is drastically different from the previous AD (who was the ex-wrestling coach) and she's shown the willingness to move on from underachieving coaches at a far greater propensity than her predecessor.
Grey still has a great relationship with the donors, but this could fray over time if other Ivies (Penn- newly flush with $20 mil) and resurgent Columbia overtake them. He's still recruiting well, and I don't see a move being made as long as that continues.