I like Obsidian a lot, but if they do get bought I hope they at least have one team not making CRPGs. I have a hard time getting into this genre in general, and vastly prefer New Vegas, KotOR II, and even Alpha Protocol to their more recent output because of their gameplay and non-isometric camera. One big concern I have is that Obsidian have lost a lot of the talent that made the writing in their older games so great. Most notably Chris Avellone is gone, but so are some of the other lead writers from New Vegas, once of which I know when to Guerilla and worked on Horizon Zero Dawn. They still have Sawyer, which keeps me positive overall.
I hope they don't just get stuck on Fable, nor do I really want Playground on it. I'd vastly prefer new IP, though maybe Playground would still be best working on an old IP since I don't think they've really made one of their own. Forza Horizon does have a lot of personality, but it's a big leap to make an entire world.
On the general purpose BC talk, I think they only way around the publisher issue is to build hardware in the box that can read the old discs the old fashioned way. If there is a digital side to it I think permission comes into play. It doesn't seem like it will be an issue going forward now, but 100% support for 360 and OG won't ever happen. Quality concerns would probably hold it up before, as I don't think MS was happy with the way some games ran like trash when played on the 360's OG emulator.