Romney would bring his team into State, and the damage they could do—even just with leaks to the press—could be devastating.
Trump would change Romney out before that happened. No doubt about that whatsoever. Romney would tow the line to Trump’s vision produce appropriate results - or be gone in an instant. That is the way Trump operates. That is Trump in control.
In that box Romney might be able to do a good job. I don’t know, but I trust Trump to know.