Personally, I think the combat worked fine. Jumping off a ledge, rolling to break your fall and wall running across a gap to jump off the wall and kick a soldier in the face before he knows what's happening is incredibly fun, and it doesn't break flow at all either. The problem I have with the combat is how they allow Faith to use guns.
When I played Mirror's Edge, I was going for the 'Don't shoot anyone' achievement, meaning that all of my methods of getting past soldiers and through levels was either a surprise kick/punch to the face or just running past them. I had no difficulty playing the game (Apart from one of the final sections, where the level design seemed more build like a CoD map than a Mirror's Edge map). A friend of mine was playing it with the use of guns, so he would normally be getting a gun, then taking everyone out when faced with soldiers. Because of this he was often asking me how I got past certain sections of the game, as the free-running options that I used weren't apparent to him since he was trying to use firepower to get through.
When you put a gun in somebody's hand, that puts them in a certain mindset: Shoot everybody that looks at you funny.
If you give them free-running abilities, and the only combat available is punches & kicks, then they start to see all sorts of new options for getting around problems that they would have never thought about if they had a gun.
This is also why I get the feeling stealth wouldn't work in a game like Mirror's Edge. Mirror's Edge is all about the flow, and when you introduce stealth elements to a game, people tend to take a more slow, stealthy approach, and this would break flow faster than a brick to the face.
One other thing I would like to see added is a bit more choice in pathways. While there are different ways to navigate around in Mirror's Edge, I would like to see these choices be a bit more varied than choosing whether to use box A or box B to climb onto a ledge. Maybe something more like going one way will get you shot at, but the jumps needed to get through are fast and easy to pull off, or go another way where the jumps are more difficult and complex but you aren't getting shot at as much (Or not at all)
Aside from that, the main thing I would like to see is another Mirror's Edge game. I really enjoyed the first one, and it's nice to have a game based around free-running rather than shooting.