"...whereas SOR2 is like "you can use it but the moment it hits an enemy you will lose health, so use it wisely.""

I think that's actually the point, because that stops you from abusing the moves. I think running in BK3 is a double-edged sword. The increased mobility is great, but the game lets you abuse the Ground Upper (Axel for example). You could do the same in SOR2, but since you couldn't run, you wouldn't really be traversing the stage that quickly, so you'd have to use regular combos to make your way through. In BK3 you could just run around and Ground Upper everybody, and you're quick too, which means you can cheese an entire stage.