Dan Saffer, director of interaction design for Smart Design, thinks the gap may be unbridgeable.

"Metro is a great mobile operating system. It's a really smart idea and a completely new paradigm," he says. He thinks that elegance gets lost in its translation to the desktop.

So how can hardware makers get past this rocky transition period?

Cheston suspects that computing will become less dependent on a traditional display. He points to projection technology and the growing power of gesture-based interfaces. A small device projecting a larger visual workspace would free a hybrid gadget from fighting with screen-size discrepancies.

Saffer thinks the quest for one seamless interface across different devices is doomed. He likes the idea of a single operating system, but with separate interfaces for navigation, file management, and apps, tailored for different hardware designs. The view could switch depending on the use case, he suggests.

Then there's a radical alternative: Perhaps Microsoft simply needs to go all-in with its Metro interface and ditch the windowed style of computing entirely.

Windows 8 already shares more than a few similarities with a concept design called 10/GUI, which designer R. Clayton Miller conceived as a way to bring a touch-style computing experience to the desktop. It's got navigational nuances that lend themselves to on-screen touch much better than the non-Metro interface in Windows 8.

Miller's 10-minute manifesto video sums up his concept far more effectively than words can, but its most powerful idea hinges on the abolishment of freestanding windows and the adoption an oversized, multitouch trackpad that correlates any touch to the same relative position on the screen.

That kind of radical re-conception could scare customers.

Microsoft is still wading in the shallow end with Windows 8, though, and its Surface struggles make one thing very clear: there is no true hybrid on the horizon. Any expectation that one slab of hardware can fully replace your tablet and your PC is both unrealistic and futile.