I think the trouble, Moet, is that none of us have figured out a middle-level explanation, sitting between "it works a lot better" and "here's the nuts and bolts detail list".
I find that, having used BFTB, I keep tripping over myself in COTA, expecting features that aren't actually there. They don't sound like much in a list, though.
It's sort of like looking at a two sports cars. Both of them can go from A to B fast. One of them is a lot more fun to drive. Why? Now suddenly we're discussing engine and steering and suspension systems, dashboard layouts, seat adjustments, blah blah blah. And looking at the tech specs, why is it a better car....? Each individual change seems small, but they add up.
Once the demo comes out, this may make more sense. They are both sports cars, but BFTB handles better.