I guess I'm not sure what you mean when you're talking about game mechanics. KF1's gun handling is some of the best, LFD is a joke when it comes to weapon handling in comparison. And the way the game operates is pretty unique. 6 player co-op defending against waves of enemies. Not saying nobody else hasn't tried doing this, but KF's implementation is fairly unique, otherwise I'd be playing something else if there was something that is the same only better.
Also, if KF isn't emotionally stimulating and the game mechanics aren't good, then what is the draw? I'm not saying KF is stimulating, but not really sure how sprinting would add to that. If anything, being harder to get away would add more tension.
I think if there is to be any emotion, the game should be more horrifying, but I don't see how sprint adds to that.
I'm also not saying they shouldn't put sprint in, it could work. I don't think anybody should really expect an emotionally charged experience from a game that is all about killing hordes of zombie like monstrosities in as many ways as possible.