Probably not the first one to request that, but here goes:
It would be very nice to have a feature for the physics behavior that simply checks if there's ANYTHING underneath the player. So we can know when the object hits the floor. Without having to do collision checks with every instance of a sprite. Check underneath through 10 pixels (user defined)... if you hit anything, it's true, if not, it's false.
Also, if physics could interact with a simple solid object... I wonder if it would make collision checks a bit faster or help the above at least?