I agree completely Fashir, both modes of erasing are valid, though I actually prefer the ArtRage Eraser to any I've ever used (especially traditional erasers). That said a toggle for the eraser to work otherwise would be most useful too. As to layer masks this would be exceptionally useful especially if I could link it to a group to mask an entire group like I used to in Photoshop when doing some kinds of work.

I would like the "clear" blend mode for any tool that lets you change it's blend mode, where 'clear' makes the tool remove pixels according to it's various properties, this would turn ink pen into an eraser just with a flick of a blend mode, or allow for custom eraser sheets using the sticker spray tool. Preferably with a way to hotkey the blend mode as a toggle.