i read this from wikipedia:
http://en.wikipedia.org/wiki/G...Seed_Destiny#Criticism

Mobile Suit Gundam SEED Destiny has been criticized by a number of people for being far too liberal in its homages to Zeta Gundam's storyline, endless uses of recycled animation (without the correct mobile suits being substituted in some cases), and the gradual "shafting" of the new ZAFT characters and complete elimination of the Earth Alliance characters in favor of the old cast in order to address perceived fan demand. Ironically, there has also been criticism of the old cast's portrayal, as some fans feel they were reduced to dull caricatures, lacking many of the traits that made them popular in the first place.

The "overpowered" one-sidedness of many fights has also suffered frequent complaints, causing the series to suffer from unrealistic shifts in warfare believability in all but a few cases which created a distinct contrast to the battle choreography from the first series. This is particularly evident during the last battle, as Kira's Strike Freedom and Athrun's Infinite Justice remain almost untouched, while Shinn's Destiny and Rey's Legend are almost completely trashed. Another evidence of the "one-sidedness" is the "downpower" of Destroy Gundam. While the original Destroy destroyed half of Berlin and annihilated at least two major ZAFT task forces before being defeated with great difficulty by the combined efforts of Kira and Shinn, the five Destroy units defending Heaven's Base and the three defending the Daedalus lunar base are trashed in short order as if they're grunt MS.

Much criticism is concentrated at director Mitsuo Fukuda for giving his wife, Chiaki Morosawa, too much creative control with the script, and caving into fan demand too easily, resulting in rocky and inconsistent storytelling. Animation director Yousuke Kabashima also critized Morosawa in his blog, for shifting the storyline on the fly and habitually turning in scripts late, and also implied that she only had her job as chief writer because she was Fukuda's wife (a suggestion echoed by many fans). Morosawa has also received heavy criticism from fans for abruptly writing Cagalli, previously a very important character, out of the story and ending her relationship with Athrun with no on-screen explanation and little reaction by any of the characters. This criticism was exacerbated by a post-series interview in which she gave explanations that many fans felt to be dubious at best. A target of particular scorn is her assertion that Athrun would need to be the leader of his own nation for their romance to resume, even though logically that would make a relationship more difficult (nations inherently have differing agendas, making a romance between their leaders an obvious conflict of interest). Further angering fans, she has also suggested that the near-last minute relationship formed between Shinn and Lunamaria under questionable circumstances is the truest form of romance seen in the show.

In terms of mecha, focus was placed on newer units such as Strike Freedom, Infinite Justice, and Legend Gundams which are often cited as being little more than upgrades of their respective counterparts in the original Gundam SEED (Freedom, Justice, Providence) used as an excuse to reuse old animations. Other main units also prove to be derivative of old designs. For example, ZAKU series, GOUF Ignited and DOM Trooper are derivative of MS-06 Zaku II, MS-07 Gouf, and MS-09 Dom from the original Mobile Suit Gundam. Also, while the Akatsuki strongly resembles the Hyaku Shiki from Mobile Suit Zeta Gundam, it also copies the "Fin Funnel Barrier" used by Amuro's Nu Gundam in Char's Counterattack. Strike Freedom has also been criticized by some as little more than a rehash of Amuro Ray's Hi-Nu Gundam. Impulse is almost identical to Strike in the original Gundam SEED in terms of the Striker packs vs. the Silhouette packs, combined with a core block system very similar to V Gundam from Mobile Suit Victory Gundam. The Destiny itself is known for a "mix" of everything - with its "Hikari no Tsubasa" (Wings of Light) taken from V2 Gundam from Mobile Suit Victory Gundam, the Palm Cannon being a derivative of "Shining Finger" from Mobile Fighter G Gundam; the 'Wings of Light' create afterimages, similar to the Gundam F91's ability when it dispenses built-up heat, from the movie of the same name; the Destiny also has the main weapons of the Sword Strike Gundam/Sword Impulse Gundam, and the Launcher Strike Gundam/Blast Impulse Gundam.

Tensions also exist between long time fans (most of whom favour UC) and the more recent SEED fans, due to the older fans being unhappy with how many past ideas reappear in the series to the point they go far beyond an homage. A common complaint from these older fans is the fact that most of the newly introduced ZAFT units were little more than recycled Zeon suits from the original Mobile Suit Gundam. Their criticism is unsubtantiated on one level: saying that the Impulse is a rip-off of the Strike is like saying Zeta Gundam's RX-178 Gundam Mark II is a rip-off of the original Gundam's RX-78-2 Gundam. In some rare extreme cases, both sides have been known to resort to insults and childish attacks. However, these cases are the exception and most fans can happily accept other's interests for the same courtesy.

Many fans were also disappointed with the ending of Destiny, as two clip shows in the final ten episodes hurt the pacing and led to the final episodes being more rushed then they would have been otherwise. Some have suggested that this ties in with Kabashima's report of Morosawa submitting scripts past their deadlines, and that the clip shows were used not to save money (the usual purpose of such episodes) but to make up for Morosawa's tardiness. Some have also suggested that the excessive number of clip shows (as well as the overuse of recycled animation) was a result of the show's budget being squandered on a total of 4 opening, 4 ending, and 2 insert themes, all by highly-paid musicians, and on hiring famous seiyuu even for minor roles.

Perhaps the largest source of controversy the series has to offer is who, exactly, the protagonist supposed to be. It was made fairly clear from the beginning that Shinn Asuka was supposed to be the main character, with Athrun Zala playing a large supporting role. However some feel the inclusion of Kira Yamato and members of the old Archangel crew from Gundam SEED limited the character development that Shinn and Athrun should have seen in an attempt to balance the series between three characters. Despite claims by the director, some fans treat his comments as nonsense (as they treated the comments by the writer on romance), especially since it was clear near the end that Kira was portrayed as the good guy (despite his alleged "straying from justice") while Shinn was portrayed as someone who had become a frantic (despite claim of his status as the protagonist) for a wrong causes (due to the villianous portrayal of Durandal). Some fans feel that it is due to this division of attention that Shinn Asuka's character did not dramatically change. Many feel this is in poor contrast to previous Gundam protagonists such as Amuro Ray and Kamille Bidan, who were solo protagonists that started as less than desirable characters but matured into better people as their stories progressed.