Well, I've finally finished watching Gundam 00 Season 1. In my opinion, the pacing was a little slower than Gundam SEED, but considering it's less monotonous and shorter, I'll take it. While they did end the season nicely, with most of the suits destroyed, Earth having united and mass producing GN-X units - the show doesn't hold off on reminding us that a second season is coming. We have Saji Crossroad seemingly being the poor fellow, having been stripped of everything valuable to him, might come into his own in the second season - hopefully doing a little more than standing around and watching people get killed around him.
They reveal that Celestial Being isn't dead, having at least two complete units - perhaps lacking a GN Drive or two - although they haven't revealed Setsuna's fate after the final battle of season one. But knowing Sunrise, nobody's dead until they've melted in a particle beam, gotten stabbed in some vital part. Getting abandoned in space with no apparent means of rescue usually means they're alive.
It's been made clear that some of our main opposition pilots are still alive (even then one that seemingly got erased in a particle beam) and some of our main character pilots are still alive.
As usual, main characters are always too powerful for their own good. 4 pitiful Gundams versus 30 GN-X units plus one Alvatore. And the only survivor of the entire conflict? One damaged GN-X. Highly amusing.