Cool initiative
!!
Personally, as developer that works on different types of projects and sometimes different editors (but not multiple OSes), I also see a couple of problems:
1. If I got it right, this is separate, additional keyboard? That means it will be next to the main keyboard, and to type on it, I will have to move my hand to it. I prefer having such shortcuts that I don't have to move my hand much from the central position.
2. I don't like the idea of being dependent on such additional keyboard - I might go somewhere with my laptop and then I don't want to be missing those extra buttons.
3. As also mentioned above, although I might be using multiple editors, I normally configure them in such way that I always have the same shortcuts.