He wouldn't bother and lol at fights being rubbish as if he'd direct every single movie. Besides Nolan's vehicular action is second to none in Hollywood. DCEU fanboys can come back when their films produce action scenes on par with the 4 chase scenes in TDKT. All we've gotten so far is bad CGI drivel.
Batman and Superman would have actually had a real conversation and we would have seen how fundamentally different they are. Nolan would have given them more reasons to fight than crayola written notes. We would have saw the birth of a genuine friendship as well.