I believe that Sketchbook Pro has potential to become one of the easiest and best animation softwares out there if it had a good timeline editor with layers and frame and maybe a frame layer editor. It will also help me a lot. The ability to keyframe and add enough motion through sketchbook pro would be amazing. We should also have a better onion skin feature that could help us with in between animation, maybe an onion skin feature that could be colored and etc. 🙂 Last of all, the ability to add sound into our animations for lip sync, music, etc.
P.S. we should be able to create unlimited frames in the flipbook feature. 🙂