Honestly, I think BioWare lost their heart after Jade Empire. Dragon Age: Origins had some great moments, but I think that's largely due to how it began development around the same time as Jade Empire so some of their better developers and writers were still there for some of it.
I thought Mass Effect 2 was the best Mass Effect, but that's not really saying much.
Indeed, if we get a Fallout 4.5 then I'd prefer it be handled by a studio that actually cares about the IP. Obsidian does because they consist of people who worked on the first two, know people who worked on the first two, and\or are big fans of the first two. They also have a great understanding of the lore. There's no reason to assume that companies like BioWare, Gearbox, Larian and CD Projekt would care enough to deliver a great product, or would be good fits for the franchise regardless of their resume.