I do have plans on making the engine commercial, but not as competition for mainstream engines like Crysis, Unreal, etc. Rather, I'll be using the engine on a commercial product which would make it unwise to release the engine.
As for modding, I most certainly want to have some modding capabilities made available to the community. I have supported the modding communities for a long time now (mostly with Unreal), so I don't have any intention on abandoning them now. I'm not sure what all will be made available, but there will definitely be scripting functionality that allows you to make your own gameplay modes and the ability to create your own ships, bases, or player models.
The engine was designed around flexibility (which is partially why it is taking a while), so it only makes sense that we give the community access to some of that flexibility. One of our main concerns, however, is giving too much to the community and causing chaos. Power is great and all, but there needs to be boundaries or people will become overwhelmed. There is obviously the danger of giving too little control, but we will make sure that doesn't happen. Please don't let this spiral into a long discussion on where that distinguishing line is---we are quite aware of it and if the community finds it wanting, we can always improve upon it.
Hope that helps explain, at least to some degree, where we are and where we plan to be.
--Joel