Seed is fine. Now Seed Destiny is a completely different story. Seed's a decent enough retelling of 0079, while Destiny is a train wreck reimagining of Zeta.
Oh trust me, the nicest thing you'll hear me say about SEED Destiny is that it's not the worst Gundam series I've seen (that honour goes to Gundam AGE).
What did you like about it?
Well one thing I did like about SEED the cast. I liked the interactions that they have with one another and some characters like Athrun, Mu and Le Cresent are some of the best parts of the series. I also think Kira and Lacus are good characters in spite of their flaws. All of which is complimented by a very good dub from Ocean group.
Another aspect I liked were the mechs and the battles. The environments were varied and helped affect how Gundam fights played out. There was also variety in the mechs both in design and the weapons they used. It wasn't just laser spam light show like in SEED Destiny or that garbage 00 movie. And of course the battles were just good.
The story, though reusing elements of the UC series, does add a twist to it and is overall decently presented.
Not to say that it's perfect though. Animation has tendency to be recycled and the character designs suffer from same face syndrome (Thanks Hisashi Hirai). On top of all that, some of the supporting cast, like Kuzzey do end up being pretty forgettable and some plot points end up being under developed like Coordinators becoming infertile. There's also the fact that some characters end up surviving shit that frankly should have instantly killed them. (Seriously how to you tank two Gundams exploding point blank?)
Also Flay Allister. She sucks.
In the end, I consider Gundam Seed to be a flawed but ultimately good series, that gets too flak because of its status within the franchise and everything that occurred around it like the trainwreck of a sequel.
