Don't get me wrong, on foot was an obvious (and necessary) addition, and I'm sure it took a lot of work to do, but Odyssey needed more for the rest of the game too so it wasn't just about that (perhaps some new ships at the very least?). And it needed to connect the two better. And yes, we did of course get thin atmospheric worlds too ... and boy was I excited for that, and I can't for the life of me tell you why I found it such a let down. I really thought flying a Cobra across a fresh landscape under blue skies would be a transformative experience, but in the end I just found it a bit meh. Sorry FD.I don't want to harken back to the Kickstarter videos in a "they didn't deliver on this" kind of way, but despite its predecessors, on-foot gameplay was very much on the cards from the beginning.

If I focus on just one thing for a moment, something that was so compelling and special that every games mag on the planet was talking about it, and even actual RL astronauts were tweeting messages of encouragement. The Distant Worlds expeditions. When I think of pre-Odyssey Elite I think of things like this. Vast, epic journeys through space. Multi-month long commitments to a journey into the unknown. Tales from a hundred different commanders all swept up in something way bigger and more important than just point scoring game loops.
But ... when I think of Odyssey I'm afraid the first things that come into my mind are a dozen indistinguishable livestreams of people running around with machine guns going pew pew, yay, I captured the flag. It's boring rubbish. It's not big, it's not epic, it's not capturing anyone's imagination, it's not memorable, nobody's talking about it and nobody's gonna remember it.
In answer to questions 3 and 4 again ... I don't know how exactly but Frontier need to bring back that sense of wonder.