It will only be effective if it comes from the dem side, otherwise it will be panned off as "political".
WRT dem side, a combination of factors could be in play. If it's a turf war, which I think it is, namely Obama/Mike/Jarret/Harris/Pelosi vs Clinton, the sexual allegations will only come from the Obama side. Danger with sexual allegations is the likelihood that those troops on the Obama side wanting to take out Cuomo may be guilty of sexual harassment themselves, and vice versa. Both sides have a black book. Hypocrisy is an ugly drug in this game.
Dynamic in play here is future of Mike vs Chelsea, I think, so a smart move would be for Trump to seed some discord into that schism, then retreat and watch it play out from the cheap seats. Payback can be a bitch, they say.