I just watched Gundam SEED CE 73 Stargazer, and I thought it was pretty good in terms of worldbuilding. It has something I wish we had more of in Gundam -- that is, a mobile suit that's not meant for war, but for peaceful purposes and to expand humanity's horizons. Said suit is also a two-seater, which I enjoyed. I also liked that there was also a neutral organization for scientific research which had a mathematician! I wish we had more Gundam stories focusing on science and technological development rather than war and action. The story captured well the idea that even though technology can amplify the atrocities of war, it can also hold hope and the path to a brighter future. The ending was evocative of 0079's ending in that there can also be a hope for peace, but this peace can only be brought about by reaching an understanding with the other side -- something which only comes with lots of desperation. This was helped by the fact that the villain was sympathetic (by the way, the Cosmic Era is super metal with its brainwashing of children into violent soldiers); I liked how his backstory reflected what happens with the titular mobile suit. I'll have to check out the other SEED side stories; ASTRAY is supposed to be quite good.