Crowder: possibly, but he was pretty bad on the Cavs. He could be a tad more useful now given that the Celtics' biggest advantage in this series has been their wing depth.
Wade and Rose: absolutely. Neither were good fits given that they're not good shooters or reliable defenders. As others pointed out, it was clear that Wade absolutely hated it there so his departure was inevitable.
If anything, the Cavs should have gone for more playoff proven vets. Getting George Hill wasn't a bad idea, but other possibilities were Wes Matthews or Tyson Chandler, who I think could have helped them.