Lets say JR Jr. wanted to draw Superman his whole career and when he finally got the chance, it's the lame hipster version in a bad 90s armor design, not what he signed up for. What happens if he refuses to turn in pages like that, and draws the Classic Superman that everyone wants instead? How do you force an artist to stop drawing underpants? Is that considered breech of contract? Do you fire him, or just get someone else to erase the underpants and add the superfluous Jim Lee costume lines?

Well, the first thing I would do if an artist drew something in a manner that wasn’t considered acceptable would be not to accept the work and not to pay him or her for it, until such a point that it met with my approval.

I don’t know what the situation is with JRJR and Superman, and if this is just you projecting or if you’re reacting to some rumor fodder somewhere. But when he was approached about doing Superman, it was post-New 52, so clearly he was going to be drawing the modern Superman. if he had a huge issue with that, then that would have been part of whatever discussions were had–and the outcome would have been one that he could live with if he accepted the gig.