Hero: I think you underestimate how bad Destiny was
I was calling it bad without anyone else telling me that, as it's flaws were readily apparent.
The SEED characters had their character development tapped out by the end of SEED. I mean really, where else do you go with Kira after all that? So they basically ignore any sort of development for Kira/Lacus the entirety of Destiny. Athrun and Cagalli regress into some kind of pathetic catharsis for most of the show, and Shinn the new lead character doesn't even develop as a character at all -- he's the same retard in Ep50 he was in Ep1. At least Kamille from Zeta (whom Shinn is based on) grew out of that phase by the middle of the show.
As for a 3rd season: The possibility is obviously there. Stargazer was extremely good for such a short little OVA. I'd be for it as long as Fukuda wasn't director. Either get the Stargazer director or someone else.