I thought it was satisfying and besides, Oh!Great couldn't have ended it better in such a short amount of time. The final attack had already happened because as it turned out, the true deciding factor was Sora's Bloody Wings vs. Ikki's Astral Magus, and we all know who came out on top of that one. Pretty surprising that the final Trick would be more of a defensive one, especially considering how this is a shonen manga.
As for Sora surviving? Think about it people, the guy practically just got the worst punishment he could ever deserve. Sora was resigned to die for leaving everything behind (literally) and what? You just tell him to pick himself up and start over? That is not something that is easy to do and probably the harshest thing you can grant to someone who is so far gone that even he recognizes it.
Regarding Ikki, I like what OG did. He left it ambiguous, which in my opinion actually works for both kinds of fans. We never know if he was truly an experiment and if he was, does it even matter? After all in the end even Dr. Minami was rooting for Sora to win all along as he considered him his greatest experiment. So really that doesn't really leave much for Ikki. I like that it doesn't matter what Ikki really is, it's what he does that defines him (totally my Batman Begins reference right here).
I don't know why some people are confused about the last chapter though. It plays out like an anime ending episode where you see different "videos" being put together to close off different characters. I thought it was perfect, and it gave that uplifting feeling that life goes on.
Thank you for those 10 years Oh!Great. Air Gear may not be perfect, but it sure as hell is one of the most unique and enjoyable shonen manga series I have ever had the pleasure to read. Air Gear may not be perfect, but this last arc was pretty damn good in my eyes. To finish off at such a high note, I can say that I'm actually pretty damn satisfied.