So what's wrong with adding feathering/AA options? Shift-drag? Don't forget, folks: PDN IS open source. If you want to make tools just go into the source and hook one in.
As for my idea of B&W alpha channel (for things like VTF or whatever the Valve image format is), it would be as simple as this:
Per pixel, make R,G,B = alpha value
And the same in reverse, but with desaturation first.
That would be quite handy.
PS: AV and AS?