I must confess that my first reaction to the UNIX interfaces back in the early 1980s was not all that positive, so I can relate! Of course, these interfaces aren't all that much younger than I am, and much has changed during the intervening years, virtualization being but one such change! My guess is that you are primarily interested in the interaction of userspace I/O and virtualization, though I suspect that non-virtualized environments must be taken into account as well.
You mention Zach and Rusty. Who else would need to be involved to make good forward progress? What forward progress (patches!) would it be reasonable to expect from sessions at the Linux Plumbers Conference, and what prework would be required in order to make such progress possible?