We just answered a few questions about NS2 in this interview on BigDownload.com. Here's an excerpt:

Natural Selection 2 is a mix of RTS and FPS. How hard has it been making sure the two game genres work together?

It's not simple. From NS1 I learned that the best intermarriage of the two genres is closer to FPS than half-way between the two. It has to be a great FPS first, with RTS elements playing a secondary role. I'm glad we didn't ship NS1 as a commercial product, as it allowed us to make mistakes on that one. Like making crepes - you throw out the first one.