I like the "new" sprint control - sprint toggle. Very handy considering I have to use one more button for dodge. But there's a problem with that - blackout, stamina loss.
I don't want to suggest increasing stamina for humans - I think it's fine. My idea is to not let player sprint when stamina is less than x. Like with jump - you can jump to certain stamina level, then you have to wait. I hope you get the idea.
Another thing, I think quite connected with previous one, is the hud - when you run under certain stamina level there's no way to see if you are currently sprinting or just running. Only thing you can do is to run move forward a bit and see if you keep slowing down or not. I suggest adding an icon for sprinting instead of overusing harry potter's symbol.
And the last one, but I think it's a bug rather than intended feature - you can't toggle sprint while flying with jetpack.