I think seeking out a nesting site with marine type units (something like Starcraft I'm imagining) would be a lot of fun! I just wonder if it would fit into the scope of the game with the direction it has been developed so far. I would imagine it getting overwhelming to an average player having to control units like that as well as base manage. But maybe you see it in a different light that it wouldn't be overwhelming.
I would really like to see an archeological type unit and can see that being something that would be easy to manage. Discoveries (like the artifact that's in the 3rd mission) would be a great way to introduce new tech into the game.
I'd like to see that advance to the point where it enables tech allowing you to build and launch another colony ship to another planet in a different star system. The reason could be that discoveries found on Aven Prime have told of a race that left it to rebuild on another planet for some reason. Now command wants you to spearhead the construction of a new colony ship (with enhanced tech from discovered alien tech) that will travel to this world. I imagine gameplay would then shift to you needing to build factories to construct certain parts to be taken into orbit to build the new colony ship. There could be a collapsible screen to see the progress of it.
After several missions and the completion of the new ship, its voyage could be a video of the journey as it begins it's trek to another star system to make contact with these aliens. And then this new planet could be the expansion!
That's my fantasy for the games future at least. Regardless I'm having a lot of fun playing it!