The whole idea behind the 800SFP is to take-off or land with the same weight in a shorter distance. In the landing & stopping case this is achieved partially by improving the braking performance by reducing the gear splay, the idle thrust delay time and making the ground spoilers more effective.
In the take-off and landing case the slats are now sealed up to the 15 position (previously 10), this gives more lift at lower AoA. The other improvements in lift (ie reduction in Vr & Vref & dist reqd) can only be made by allowing an inc AoA, because the wing is unaltered. The increased AoA reduces tail clearance which is why the aircraft has a two position tailskid which extends further on landing.
These features are also standard on the -900ER and some may become available on -700s.