Okay, so here I am. There are only a few points I feel like contending you on.
The AGE System wasn't on the Diva. The AGE Builder was. The AGE system itself is inside the FX.
I also think you're too hard on Kio. Yes, him being a kid does warrant him some leniency. He's not a soldier, and aside from Flit telling him so, he had no strong reason to hate the Vagans. He is incredibly naive, but again, he's just a kid. Even so it's not like he stopped fighting, or started attacking both sides. He was still mowing down Vagan grunts and helped win battles. He only interfered with his allies that one time but that's because the guy shot at an already disabled opponent. The pilots his spared never came back to cause further problems either so it's not like that had any negative consequences. Him sparing Zanald might have been bad, but he was killed by Zeheart before he could do anything.
It's erroneous to call him a coward. A coward wouldn't kill because he's afraid to, but Kio chose his path and he stuck to it. He didn't waver or give in to the pressure others were putting on him. Certainly a better choice than him being Grandpa's little genocide machine. And in the end he was right, so there ya go.
I don't agree with him 100% (I think some people like Zanald need to be killed) but he's hardly the worst Gundam protagonist. I'd certainly take him over Kamille's whining and saying "How can you kill others? I'll kill you!" Kou is still the worst Gundam protag in my book.
As for the Vagans themselves, try having a little empathy and put yourselves in their shoes. They were abandoned and left to die in space by the people of Earth and you expect them not to resent that? After God knows how many years of putting up with it, they decide they don't want to just wait around and die anymore. It wouldn't be hard for some one like Ezelcant to rally the people. Imagine yourself trapped in a hole for years, then some one appears and offers to get you out. You're not going to weigh your options. Yeah it took Ezelcant awhile to do stuff, but it's not like they had any other alternatives and I'm sure at that point a few decades aren't going to make much difference to them.
I'm sure they definitely would have turned on Ezelcant if they knew his true plan, but that never got exposed to them. It is true them as a faction needed some more focus put on them outside of one cute sickly girl.
I do agree with a lot of your other points but I'm still not so harsh on the series. It faltered a lot but I still enjoyed myself and would rank it higher than Zeta (not the movies), Victory, and Destiny on my favourites list.
"In the end, the world doesn't really need a Superman... Just a brave one."