1)Emulate Pressure with the mousewheel whilst drawing
2) the ability to hook up to game controllers and midi controllers in order to dynamically adjust variables and generate numbers using controller position, velocity, and possibly coordinates (touchpads and so on). this means that one guy could be drawing whilst another is randomly messing with the controller.
3) Music can generate values for for your brushes as well!!!! values such as amplitude and levels from spectrum analysis can have awesome results!
4)Low Ranking suggestion... wii controller support!!!! it would feel like squirting paint at a screen!.
5)paint that melts and drips... liquid physics? possibly not the style or purpose of this program.
6) Dynamically coloured brush that works! adjusts RGB Trans and Gradient based on dynamic values.
7)Box/ Polygon select.
I i see more work done, (judging from the demo) ill buy it for myself. im gonna buy a copy for my brother! ...