From your Kickstarter video.
I love the idea of the base development. I'm all for things to spend our hard won cash on.
More items/item progression is another thing I like. Eg: unlocking/finding/buying better weapons/gear over time.
Non-combat missions will be nice variety.
All of the stuff you said sounded great, but you asked for what features we particularly liked.
I like all of it, but I'm more enthusiastic about the above (not that I ONLY want the above implemented or will be upset if it isn't).
I'll be happy for whatever extra you are able to add.