It would be helpful to be able to save the brush and color-picker histories with a BKD file. I find myself returning to a WIP and there is no easy way to add another stroke that I suddenly see the piece must have without recreating (usually without 100% success) my brushes.
I'm aware that I can save my brushes, but that is somewhat tedious and impractical for brushes that I will never use on another file. Not to mention that the brush list will get unwieldy very quickly!
Obviously, colors are easier to re-populate with the picker, etc. but having a saved history would be a big time-saver.
Other ideas:
* Perhaps the program could be modified to have a standard set of brushes for a new image and a palette of brushes that have been used in the open file?
* Would it be possible to create a way of organizing the brushes into a tree/folder/category to group similar brushes together?
That's my two cents worth!