Just a general thought. At some point (for consumers anyway), these paradigms will unite. As such, what will follow is the necessity for window management that can handle different use cases. Right now the only OS really attempting to bridge the gap is Windows 8, which is currently an unfortunate juxtaposition of two battling WM's rather than a seamless unification. Apple isn't really bothering to unify at the moment, Google isn't sure what it wants to do, and desktop linux (though I primarily work in linux) really is a less quality product.

I'd argue that window management innovation has been a terribly sorry state for quite a while. I mean, I would venture a guess that the increasing prevalence of browser-based tools is in part a result of a lack of [good] innovation by WM's (of course, as well as better tools for web app developers). Mobile OS's have been the only thing to really shake things up.

I'm not sure exactly what my point is here. Just a general feeling that we're going to continue to debate on the differences between tablets and pc's until someone actually goes ahead and creates a useful WM for both use cases. Windows 8 is an okay start in that regard, but I feel there's a way to do it better.