I think those kinds of gestures are cool, but they tend to be a little hard to remember, and they're very non-intuitive. By non-intuitive, I mean that there is no way that you could figure out how to work them just by messing around with the software, you need to read documentation to learn them. These qualities kind of narrow their usefulness to a fewer number of people.

On the other hand, they do provide a lot of functionality without using the keyboard.

I've tried to stick with just one single gesture of click+drag for now.

- Michael