What I mean is that draining energy for just sprinting was one of the worst design decisions I can ever think of. It just killed mobility that Crysis 1 had, plus there were moments were I was getting shot and couldn't run to cover, instead I decided to walk slowly to cover and take some enemy fire because running to cover will drain my energy and make even more vulnerable. No one can get behind such terrible decision.
I can understand why that was frustrating for you and I will admit once or twice I found myself annoyed because I tried to sprint and was out of energy. But really, energy recharges ridiculously fast, especially with the upgrade for faster healing, and ESPECIALLY in comparison to Crysis 1.
But to me, it just reinforced the idea to me that within the logic of the universe, you are just a guy, and the suit is the only reason you are any kind of badass. If the suit is out of energy, you are really exposed and kind of momentarily fucked. So you learn to compensate and adjust your approach accordingly. It sits better with me than sprinting and then being "out of breath" or whatever after 3 seconds like in other games, anyway.
Edit-- Forgot that there was normal sprint in Crysis1 that you could use instead of 'speed mode.' It was a shame that Crytek nerfed sprint mode in C2, but I can see how they would need to limit it for the sake of gameplay. In smaller arenas, being able to sprint everywhere all the time would kind of break things. Hopefully they find some balance in Crysis 3, if indeed it is more open like the first game.