Rooney would be an excellent "super sub" if he'd be excited to play such a role, be ok with not coming into the match when circumstances don't warrant, and to be 100% clear he has to play within the system and not just do whatever he pleases.
He still has something left, and still has great desire. But if he just wants to freelance and put on a show of his skills, then MLS is where he needs to be.
And I worry that the running him into the ground last season already took too much out of his legs, and it might be too late to get that great "super sub" year out of him. We could have had two full seasons of it with a proper manager here from the start, but it was not to be.