Relena seems like another Lacus, but if you really analyse her background and conflicts she does have a bit of Cagalli's shadow.
After Sanq kingdom was restored by Zechs, she was installed as the ruler of her country because Zechs felt guilty for his military ways which conflicted with Peacecraft's ideals. Noin, being the lovesick heroine, stuck by Relena and aided her in her ruling of the country using peaceful ways. Despite her attempts to avoid war (hence upholding the Peacecraft name), Relena proved to be just another symbol of power, instead of having real authority.
Romfeller attacked Sanq and established their own faction with brute force, and after succeeding, they elected Relena as their political representative to show their "peaceful" intention. However Romfeller was easily defeated by Treize's new toys, then the story arc shifted to Miliardo's White Fang vs Treize's OZ/Earth remnants. From there onwards Relena's role diminished since her role was based mainly on Earth.
Relena wasn't a very well written character, but she surely ain't as irritating and preachy as Lacus is. At least she is still human and faces situations which she has control of.
The best twist in GW happened when OZ entered space and won over the colonies, which the Gundams were supposed to represent and fight for. Talk about being backstabbed by the very ones you are supposed to protect. Without that part, GW would have been a very plain boring SRW-pwn-all anime. In the end, it turned out to be yet another Char's Counter Attack...

I simply didn't like the change in Miliardo's character, but since he is the exact replica of Char there's little difference to expect.
Noin, on the other hand, is a pitiful character which went unappreciated throughout the story. She was supposed to be the right hand person of Zechs, yet her role was lesser than other female side characters such as Emma and Reccoa.
Overall I prefer W over X although X has much better grunts which don't blow up like fireworks whenever a breeze blows by. X's storyline is too weak and lacks focus, and we get one villain-of-the-day in every episode.
Seed is not based on W... it's a parody of UC.
OO however will sound like a cheesier, kiddy version of W.
Prove me wrong Sunrise, prove me wrong.
Do you know why I know girls like GW more than GS? My sis simply adores it. And considering that my sis's HDD is filled with all that mucky Yaoi (I had the nightmare mistake of copying her anime collection and had to gouge my eyes after that), she's a perfect example of a female anime watcher. GAH!! THE YAOI!!!
Anyways, I do feel that GW had just enough elemant of Bishi that is balanced with a true gundam world that cannot be emulated by GS, which IMO seems a more blantant attempt of selling their product. Looking back, Destiny killed anything that was good in Gundam Seed. Shinn Asuka was supposed to be the antihero, we are suppose to like him as he has all this angst. But HE WAS f***ING ANNOYING! There was nothing good that I can find in his characther. Unlike Kira "I am Jesus" Yamato who fought for what he believed was right but will admit his mistake, Shinn was like Suzaku of Code Geass. "Fight for what I believe him" was his motto to make right all of his decision, even if it was really orders by the higher up. He has no backbone, heck, i doubt that he even have a penis. Compare that to Heero Yui, a pilot that don't even need a space suit, rectify his own bone after it was broken, HE WAS THE ULTIMATE MALE EGO that both male and female can relate. He don't complain, he just do his job and GTFO.