Good question, and the answer is yes. I think we did.
I'm not going to go into specifics (mainly because its been a few years and I don't remember everything) but there were definitely places where, when I watched the series through after we were done, that I wished I could go back and rewrite bits, or expand other bits. I would have loved to have gotten into the back stories of all the Ventaran riders for instance.
One of the problems on the show was that we wrote and shot all of it before any of it was aired, which meant that we didn't get any fan feedback until it was way too late. We couldn't fine tune it as we went.