Firstly, they need to put their roadmap on the forums and tell us where they're going with it. They obviously need to work on a deeper layer of content. I'm not going to say what because we all have our own idea of what we would like (I've already said what I'd want in previous threads anyway) and I'm sure the devs can work out good game play mechanics.
MP needs to be completely reworked imo. They had Kickstarter, they had beta and now they had 300,000 sales at $60 each so they have money.
What will I do with the game? Isn't that obvious, like any game, once it becomes boring you cease playing it. Take DayZ for example, which I basically take the same approach with ED. DayZ is unfinished but they have a roadmap (at least) and have good updates with meaningful content. I'll get in it, play it for a week or two and then leave it for a few months and come back to it again. If ED is going to be developed then I'll most likely do the same approach.
I don't really care how long it takes - I'd rather have a great game than something rushed. However, I am a lot more patient than most people and I recognise the fact that the majority of players need more and need it quickly. The life of the game I want depends on the money that current players are willing to shell out so if the next DLC doesn't offer much more gameplay elements, don't expect great sales.
Even then I don't know if it will be enough - Some of my friends got the game and played it a lot. Now they're bored of it and don't read the forums and have lost interest. They're customers that aren't going to bother looking for the new DLC because they moved on - how many more people are like this?
ED rushed the release and by the sound of things, didn't listen to the beta guys who raised issues about content and MP. What this has done for the future of the game who knows. At least the healthy sales of the game are known and other people are making space sims again so who knows, maybe ED will fail but somebody else will make something better in its place