Honestly, the only reason why I'd want WMC back is for cable TV, but now that I have a TiVo, I really don't care. What we really need is a good 10-foot UI that contains all the functionality that's beneficial to a computer. So, at this point, I mostly use Plex and Chrome for everything. I have no qualms with taking a keyboard out and just typing. Is it a bit awkward? Sure, but I get all the benefits of a desktop (no ads, multiple tabs, etc.) with the minor annoyance of dealing with a keyboard and mouse. (The mouse just sits on my side table anyway.)
It would be great but for such a tiny audience. That ship has sailed. People aren't going to use full blown computers to power media consumption on TV. No way. If they packaged it into the xbox and worked with cablecard, maybe they'd have a tiny business with that. But too little, too late and too much work for little payoff. Sadly, they have to look at the business case of everything and this just doesn't fit. I wish it did. In fact, word has just come out that MS has killed plans to release a small xbox branded TV streaming device to compete with Roku, etc. It's probably the smart decision for the company in the long run, but I would prefer something by MS since I am a MS fanboy and apologist.