There are 7 panels on each wing to kill lift 5 of which can be used in flight so if you need to get down fast, normally you can. An emergency descent with gear down and speedbrakes extended, you descend like a rock. As someone said....you are never too high. But that may not always be true. In icing conditions you have to keep the thrust up at 55% N1(70% in heavier icing) and at lower altitudes, the rate of descent is quite slow(500-1000 fpm). With an ATC restriction of speed below 200 knots, you can't use speedbrakes, so extending some flaps seems to work. Only two of seven leading edge devices on each wing come out at the first selection of 2° but all slats and Krueger flaps come out with the 5° selection.
Looking at the wing when on the ground an flaps fully extended, it seems like it makes almost a half circle from lowered leading edge to aft trailing edge. All spoilers extended make it look even more impressive.
My manual does talk about not taking crab out for landing in crosswinds on very slippery runways but cautions about reverse thrust drifting the aircraft toward the downwind side of the runway when not aligned with the runway.