On the original question....
I imagine atmospheric landings will happen, it's not on the road map we've been shown for next year, but there is talk of additional paid for updates, so there is a remote chance that might be one of them, but going on current information, I'd guess 2019 (but we might find out more over the next month).
I don't think we'll ever get space legs in the way we imagine it, unless it turns up as a sort of CQC like separate game mode. What we might get, is a remote drone, this would let us make repairs on the outside of the ship or fly inside other ships or bases to scavenge or repair things.
The problem is, what do we actually want space legs for? I think I want it, but not sure what I'd do with it after the first few "oh look I can walk round my ship/some bits of a station" moments, and if we want fps style gameplay, well that's a different game. Either way, I don't think it'll happen unless it's a separate game mode, and that's 2020 at least.
Procedural cities, there are already the large bases, so in theory, big city things could exist. Again, we'd need a reason for them to exist, otherwise they'd be like the current cqc structures in game, look cool but no reason to visit twice. I guess it would add to the texture of the environment, anyway, I suppose it's possible, might turn up in two years or so if they did.
I think, the reason we want all of these things is more about the fact that currently we are lacking gameplay in what we already have (especially for people who have been playing this for a while). If combat, exploration, mining, trading and research all had development, we'd probably not care so much about space legs etc. If "beyond" adds in more depth to the existing mechanics, then we'd be happy. The mistake would be to just add on more "headline" features without improving the current core, in my opinion
Honesty time, I was at the expo, I was, happy but not thrilled when the beyond road map was explained, I guess that it's less exciting to hear "were going to make the stuff you already have better", than it is to hear "look, totally new things you never expected". But, I was secretly hoping to hear something like space legs or atmospherics lol, oh well.