Guys this game has a jump button, it's your legs (A or X), or your free hand, press either as you're running towards a wall and you'll vault over, or put one hand down and spring over.
The free run thing is when you want to just automatically lerap from object to object, very quickly, and in that case you simply hold down the A button and the character will automatically jump.
Now, anyone who's looked at the video's can't tell me this is a bad thing, seeing the guy leap from railing, to railing, onto a wall, onto the roof, off the roof, swing from a beam, to another beam, to another beam, leap off and land behind your prey...it's damn sweet.
Having to struggle with timing each jump, in an action game like this, would probably be beyond frustrating. You miss one jump, and your prey gets away, and then you either have to kill him the hard way(probably fight a ton of gaurds), or reload...with this implementation they make sure you feel like a master assassin and aren't worried about platforming, and can concentrate on strategy and technique in your assasinations.