Nice! Yeah, having played with it, I agree, there's not near enough control. Different shape marques would be nice, an dthe ability to deform TO conform to a shape (such as a spherical or boundary blend surface) or at least datum curves would be awesome. As it is, you just keep tweaking. It'd also be nice to have more control over the outcome, like if you pull on the central point, how does it deform it all the way to the edge?
Nice work though!