I just found this neat idea over at Jason Schleifers page. http://jonhandhisdog.com/forum/index.php?act=ST&f=21&t=901
The idea is to have the possibility to draw into the viewport and 2D sketch out a rough animation before animating the rig. I think this approach would be very intuitive and a great addition to the "Flatten scene keys" pose to pose approach.
What do you think about it?