How is this any different than when Gilroy came in and did the same thing for Edwards on Rogue One?

Clean it up. Finish it up with the help of a capable director like Kasdan who also wrote it. Ron Howard is a polished and established director you would want to get a situation like this done how you want. Re-hiring another younger director at this point of the film would make no sense. I wont be surprised if the film still has a lot of what Lord & Miller brought but just toned down and done more of how it was initially planned amongst them all.