I always wondered how Superman would have developed if they had left him able to "leap tall buildings in a single bound" instead of changing the concept and making him able to fly/levitate.
Basically, you'd have Superman jumping like the Hulk. The original leaping is in keeping with the dense molecular structure idea but it isn't anywhere near as cool. Maybe they would have eventually made him run on air like the Flash, but flight is as seminal to Superman as he developed as invulnerability or X-ray vision.
I mean, has anyone ever heard of a story with a non-flying Superman? I haven't.
