I hear it all the time. "Hey Matt, what if, instead of building Mega Man or his upcoming Mighty No. 9, Keiji Inafune had ended up designing a Super Mario Bros. game?"
It may be the single most asked question of 0HITPOINTS and it's so funny that you would ask that *today* of all days.
I love this whole idea of getting developers to sit down with Super Mario Maker. People who enjoy and people who make games were profoundly impacted by Super Mario Bros. and to see the pure joy in Inafune's face when he's working on making his own level is wonderful. There have been multiple videos (which you can find by clicking on the one above!) but this one stood out to me.
Who would have thought the man behind those brutal Mega Man games had a heart?