I find it interesting to think about virtualization on a spectrum with passthrough at one end and pure emulation at the other. Particularly when applied to I/O peripherals, if the bulk of the I/O can effectively be classed as payload, stepping slightly away from passthrough while maintaining roughly the same layer of abstraction grants the implementer considerable liberties in implementation with very little overhead.

If one were to look at storage, specifically, the move to 4k block sizes would seem like a particular boon in terms of increasing the volume of data covered by any given IOP.

Disclosure: Jon works on virtualization for Compute Engine :). (and I work adjacent-ish)