From arecent interview with Chris Roberts (see http://www.robertsspaceindustries.com/chris-roberts-answers-your-question/
The Wing Commander games didn’t allow much content creation, but Freelancer continues to flourish because of mods. What is your position on user-created content?
Absolutely for it! I love what the Freelancer community has done, and I’m impressed what other communities like the Skyrim or Team Fortress achieve with good tools. There’s a lot of talent and creativity out there and I fully intend to enable it and support it in my new game.
And another one from FAQ (see http://www.robertsspaceindustries.com/draft-faq/)
How will modding work?
Players will be given full control of their game! When operating private servers, players will be able and encouraged to mod the game. It doesn’t stop there, though: we hope to institute a ‘mod approval’ process that will allow the best of the best player created ships and other additions to be integrated into the central persistent world as well.