should be simple to do but it would add so much more to the game
to make it more rpg-ish armour, weight carried,spells and perks would affect the speed of being able to climb ledges.
some other climbing and falling features that would be fairly simple to add
falling animations (a bit of screen shaking when falling from a big height )
landing animations (some headbobing in first person would be nice)
the ability to roll (pressing duck when about to hit the ground? ) to reduce damage
the ability to let go of a wall or jump off
sliding ability ( runing down a hill or rooftop or maybe to ice and then ducking to slide across on the body would be fun)
more complicated things ( such as things done in mirrors edge. mirrors edge is the best thing to base climbing and acrobatics off as it is a lot more realistic than assassins creed or prince of persia)) or realy complicated things (such as controlling arms with the mouse and legs with they keyboard) would be awesome