Haven't played Mirror's Edge, but I finished Quantum Conundrum last night. I found it quite satisfying. Indeed, there's several places where the first person perspective works against the precision jumping necessary. I didn't find any of this too conflicting until the reverse gravity puzzles where I kept boucing off the ceiling and falling to my death because I could not gauge how near I was to it and keep my eyes on the path I needed at the same time. I also got fried by lasers a couple of times because I didn't get that the bottom of my character box was not yet over them. Still, it's nowhere near as bad Yahtzee makes it sound, although the reverse gravity puzzles were hardest to me because of the other detail, the ambiguity of how the physics works.
In any case, I agree that first person platforming has always felt a little off to me, compared to PoP or Tomb Raider, or Rayman, or Sonic, or.... etc, where you can see where the character IS, which is the whole point of platforming. A strange mixture happens in Amnesia, where the first persons perspective is crucial to the atmosphere for fear and the smooth interaction with the objects on screen (great engine, I insist) yet in some situations (few and far between) the perspective makes jumping from one place to another, or climbing, rather cumbersome.
Oh, and Yahtzee, your friend trying to infiltrate the building in DX:HR by jumping and failing totally didn't get the point of the game. I remember about 3 different ways to get into that building, if it's the place I'm thinking of. Only one required jumping.