I enjoyed the fact that the environments and even the majority of enemies were fairly realistic. You're not JUST taking on machines or giant monsters. Most of the villains are people with guns and armor. Hell, you even see a lot of the weaker mercs at the end. The environment is what I expect from a corporation. If they had a giant infrastructure like Half-Life 2, I would bet the government would look around and say, "Okay, so what's behind the force field and three foot steel door?" I liked the leaning thing because it allowed me to avoid getting hit. I scarfed up far more health kits in the second when I had to put my belly out there for everybody to see. And the slowing down thing I actually never took note of until the second time I played it through. I ran the entire game without needing it once. Sure, it made life much easier in retrospect, but my online play was much improved for learning to work without.
And yes, the scare factor was better in the first.
But I will agree that when I hear a franchise has been handed off, I worry that the game will become an entirely new beast. Fallout 3, Homeworld: Cataclysm, and Gothic 2 have proven that it's not always a bad direction, but Battlezone 2 and Fallout 2 (only in part) show it can be otherwise.
Btw, WHO'S YOUR DIETY!?!