A few years back, I had set up a macro to do exactly this with Keyboard Maestro. Granted, that'll cost you probably a lot more than what this program eventually will. But it is a handy method. One thing I think would benefit this new program would be the ability to have the same hotkey both tuck and untuck a window. That was one of the nice features of the original Unsanity windowshade was that command-m would shade and unshade. My KM macro is set up to do this, and it's very handy if all you want to do is temporarily move only a single window out of the way and then bring it right back. Indeed, having played with this approach for years now, I would bet that most people will not want more than a very few windows pinned to the edge of the screen.
I miss more Unsanity' ability to minimize in place (or put the minimized windows on the screen edge). It was a nice system of clean window management. You can do this with the dock, but you're also stuck with everything else that's on the dock as well.
Anyway, I hope this new program succeeds.