Sometimes I wonder, what if Michelangelo had deadline.

It's very likely that he had deadlines.

He often worked on commission basis, and for example The David was basically him finishing the work of a bunch of lazy bastards who couldn't get their chisels moving fast enough through the giant block of marble.

I also think there were deadlines involved when he turned into a crimefighting turtle, I mean catching mobsters isn't done at one's own leisure.