I don't quite understand why people often want games to be open-sourced once "done" these days. Maybe I'm not seeing it from some perspective, but open-sourcing something largely removes the developer's ability to make a living, requires a large team of active contributers to actually benefit the game, and can have a reasonably hefty legal overhead where any non-FOSS libraries have been used (in cortex command, I believe the fmod sound engine is non-FOSS, but maybe their licensing has changed?).

All of the game content in CC is modifiable, meaning that building more missions in the style that you want to see is possible even if DRL aren't interested in doing so - which means that the open-source aspect is available where it matters most anyway.

Continuous bug fixes and feature development is a fairly significant advantage to OSS for the fan base.

Anyway - what would I like to see in a sequel? Actors which can construct bases - warping them out the ether section by section (like nearly all RTSs) should be fine. Preferably according to a pre-defined, player-set blueprint. Ideally actors would also able to move other actors (like turrets, doors and things) into final location from the dropship landing bay -- again, according to the blueprint they're following.

It really depends on the maintainers, I see a lot of OSS projects that kinda peter off because the maintainers just stop approving patches. There are some really nice success stories though, like Warzone 2100.

There are some things that are just not possible with CC due to engine limitations. Open source would allow more things to be possible. I think that's pretty simple.

Development, or the tweets/dev posts to show thereof.