I have not played RE5 yet, my 360 is going in for repairs, nor have I played Dead Space but I'd like to point out one very important fact that you seem to have overlooked with the comment that you can "run and shoot at the same time", and that is that while it is possible to do that it is impossible to do that and accurately aim. I don't see to many sniper's running, jumping and shooting. Also very few head shots or weapons shot out of the air are possible while doing this.
I've played many games where running and shooting are possible but, in the interest of conserving ammo (the first time through at least) making every shot count is important.
With that said though, I will have to check out Dead Space (if its on 360) and see how "near perfect" these controls are.