Oh, I fully understand, I wasn't really expecting it (the Q) to support the HD PVR, and really, I don't even care (sorry, don't mean that to sound harsh, it's that the Echo is more interesting to me than the Q).
Just as a bit of background, (and I'll try and keep this short) I'm a Dish subscriber and use an HD PVR, and R5000 or Collossus for capture. Currently I use SageTV on a PC for the backend and SageTV extenders for the frontend. This setup gives me all the TV, plus Blu-ray, DVD, MKV, etc at each TV with one device and a single UI.
Given that SageTV has been suspended (if not killed by Google entirely) I've been on the hunt for a replacement. WMC seems by far to be the closest replacement DVR function wise, but their limited extenders and lack of PC clients makes it impossible for me to replicate what I have now, that being TV+videos (DVD/BD/MKV) with one device/UI. I've got a "lot" of fellow SageTV users in the same pickle.
So the announcement of the Q+Echo is very interesting, primarily IMO because it sounds like your Echo extender will finally break through the "silly" limitations of WMC when it comes to multi-room capabilities (ie only works with extenders and extenders suck for media).
If the Q supported USB tuners like the HD PVR that would be icing, but if just the Echo supports (as someone above said) MyMovies/MediaBrowser and DVD, BD, and/or MKV, then it's probably the biggest news to hit the WMC world cablecard (which as a Dish user doesn't help me) and you will open WMC up to a lot of SageTV users. I know personally, if I can build a WMC machine with my HD PVR/Collosus/R5000, and the Echo supports MKVs and MM/MediaBrowser, I'd be interested in one for sure (for evaluation) and likely at least two to fill out my system.