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Appreciate that DB is into astronomy...great...but I'm not.
I would like an interactive game experience, not merely a sandbox where I have to bring all the imagination, and Elite is a bit too much like that at the moment.
......
I think Elite is not your "game", because it was that way, and I don't think it'll change much.
With all that "Rather have 1000 planets and more content, than 400.... etc" - you missing one important point - Elite is one of two Space-sims/Sci-fi games (as of now), which are using nextgen idea - procedural generation.
We have 3 space-sims in development right now (yes E: D development didn't stop with release). One of them is using old tech to make "interactive game" with new graphics. It is not something bad, it's just not something new.
Procedural generation on the other side is new (on this scale of games), and while it give developers a lot more possibilities, it also make it hard to put a lot of different content from the start. Plus, there is no examples how to do it right, so it is almost pure invention of something new. Only time will tell if it's good or bad thing.
And if you don't like it, that it is simply not your cup of tea. Because I don't think that developers will change core technology, especially when it is this good.

So don't be sad/annoyed because developers don't want to make game more themepark'y, it just the way this game is/was planned/would be. Maybe another one from "current 3" will be more like you like it.
To OP:
I think near future of E: D
- Continue to iterate and add features to existing game mechanics/interface/things/etc.
- Proceed with ingame story and events
- Adding new ships (have no idea at what rate)
- Start work on "Walking in space stations" (it could bring hangars, walk in ships, and other changes to existing stuff)
- Then "start with landings on airless moons"
- Then planets....
What are time frames for any of those - have no idea, as there was no official announcements. And it is not likely that announcements of this importance will be given as an answer to a forum post. But I thing we will see at least "Walking in space stations" next year in december
