Hey guys,
I know I'm a bit late in this, but I thought to mention it anyway.
I have been sporting a tobii Eyex (or Steelseries sentry... Same thing) for some time now and use it in a number of games and simulators.
Given mirrors edge is all about looking forward to the next iteration in your flow, I think the eye tracker could prove to add a unique experience even if it's just it's screen extention feature.
It brings higher level of immersion and could prove useful in aiming for the right spot.
Some may also know TrackIR or other head tracking solutions, but for this no head movement is required. Just a shift in your gaze can place focus where you look at.
I don't know how else to explain it, take a look at the supported games and judge for yourself.