pressure sensitivity was something that the DSphat and DSlite(?) allowed because of the type of touchscreen it uses. i think it was capable of producing inputs that had variable pressures by checking how much of the grid is registering. say, a 3x3 square is a touch grid. if you touch the center square lightly, that registers a touch but the neighboring squares don't. however, press harder and the touchscreen squishes outward, registering the squares around the center square. well, at least that's how I think it works.
anyways, even with the absence of pressure sensitivity, they can just as easily employ other features to accommodate for that-- just add a slider that dictates pressure sensitivity (how hard or how light the stroke is). i also wanna see the ability to use textured brushes, different brush heads (flat, round) and different strokes according to the brush head (use flat strokes or just the edge on flat heads, full or tip on round heads).