This is an interesting idea, but if you're open to feedback you need to keep a few things in mind...
1. A cloud based DVR is a WONDERFUL idea and should be the norm, but 20 hours is ridiculous. If you're doing this with shows stored back in your data centers, you keep one copy of the show, and an index for each user's account. It costs no more storage to keep these recordings around for more than one person. Make this more attractive, put a 1TB cap on the DVR for sanity if you have to (you really don't, storage is relatively cheap these days) but make it "virtually unlimited."
2. This ignoring Android TV stuff just has to stop. The Nvidia Shield is one of the most popular streaming boxes out there now. I can install Xfinity Stream on my Pixel 2, on my Pixelbook, and on my ancient Nexus 7...but I can't install it on my Android TV device, where I would most prefer to use it?
3. As some others have mentioned, for the love of all that is good, please don't limit our show and channel choices. If we can get it on the traditional DVR, let me have it on my cloud DVR/Instant viewing. If I have HBO, let me watch my HBO on it (and ahem, again, let Xfinity be an authorized provider on Android TV devices for HBO Go! 2 years now...at least...)