One thing I miss a lot (across controls) is to be able to change the animation easing effects.
Currently, all animations, runs at a fixed speed. It doesn't speed up or slow down in any way, doing the animation (linear animation). This would be pretty awesome if it was possible, since that would give the control/component a lot more professionel look in the users eyes.
There are multiple options for easing the animations, and it should be (as a minimum) possible to select between a fixed set of them. Examples of some basic options could be the ones Apple usually use: