The Gundam franchise has basically become the face of mecha anime. With more than thirty years of movies, TV series, toys, and merchandise, it is hard to imagine any anime fan who is unfamiliar with the Gundam brand.
While the mecha genre is all about giant robots fighting, stories rely on characters to create narrative drama. The Gundam pilots, far more than the machines, give pathos and tension to the series. Some of these pilots are absolutely brilliant, while others have less intelligence than the metal used to build their machines. These are the five greatest geniuses people to ever pilot a Gundam...and the five dumbest pilots:
10 Genius: Amuro Ray
Amuro is the original Gundam pilot, being the protagonist of the 1979 series Mobile Suit Gundam. He is a competent pilot who gets increasingly better over time, but by the time of the film Char's Counterattack, he has become a seasoned savant of mobile suit combat.
He understands how to make his Gundam respond to his needs, in part due to his growing newtype abilities and in part due to his sheer intelligence when it comes to all things mechanical. Unfortunately, over time, he alienates himself from those he cares for, becoming withdrawn as the stresses of war weigh on him.
9 Dumb: Sayla Mass
Sayla Mass is another character from the original Mobile Suit Gundam. She is Char's younger sister and a student of medicine. During the One Year War, she was stationed at the White Base.
She also piloted the RX-72-8 Gundam, as well as a number of other mobile suits. She is a fairly competent pilot, but has a naive streak that makes her notably less thoughtful than most of the other Gundam pilots.
8 Genius: Char Aznable
There is a joke in the fandom regarding Char and his second alter ego, Quattro Bajeena, that they really are two separate people. Of course, characters with dual identities are a major motif through the different Gundam series, and Char is just one such example, but as he is one of the most important characters of the Universal Century timeline, it is important to acknowledge that Char--a strategic genius--was under the assumed identity of Quattro when he piloted a Gundam.
Charismatic, passionate, and arrogant, Char is a natural leader and is driven by a sense of pathos that spurs him onto victory. He is also consumed by a desire for vengeance, one of his defining traits. As someone who is gifted in all forms of mobile suit combat, he is a natural fit for a Gundam.
7 Dumb: Jerid Messa
The Titans are the main villains of the Mobile Suit Gundam Zeta, where they are consistently depicted as arrogant, petty, and needlessly cruel, all traits which Jerid depicts as a member of the Titans.
Even when he is training, Jerid is incompetent and screws things up, as shown when he tries to get comfortable piloting a prototype for the RX-178 Gundam MK-II. He crashes the mobile suit into a building. He flees, leaving the Gundam behind, and a short while later, it gets stolen.
6 Genius: Trowa Barton
Many audiences outside Japan first came to know and love the Gundam franchise after watching the series Mobile Suit Gundam Wing. Set in the alternate timeline of the "After Colony" universe (as opposed to the Universal Century timeline), Wing's five main Gundam pilots were all trained as child soldiers to fight against the forces of Earth on behalf of the space colonies. As a result of their upbringing, most were mentally and emotionally stunted, so that they come across both as idiots and geniuses, depending on circumstances.
Of the five boys in Wing who are Gundam pilots, only Trowa Barton is competent and emotionally grounded. He demonstrates social graces and a sense of subtlety his fellows lack, having all of their mastery of technology, combat, and computers without suffering the same failings as the others. He may be jaded, but Trowa is a true genius.
5 Dumb: Duo Maxwell
If Trowa is the one Gundam pilot who turned out all right, Duo Maxwell is the biggest idiot of the five main pilots in Wing. He is a surprisingly nice guy and is brimming with confidence, using his brash recklessness to drive him to success, where arrogance makes up for a lack of intellect. That said, unlike other characters on this list, he does not think less of others in his arrogance. Rather, he just thinks highly of his combat abilities, referring to himself as the "God of Death."
Despite his confidence, Duo is usually the last person to know what is going on in any given situation. Even when set alongside other meathead Gundam pilots who are notoriously dense, everyone else figures out what is going on long before Duo manages to get a grip on situations.
4 Genius: Zechs Merquise
The last character from Wing on this list is Zechs Merquise, also known as Milliardo Peacecraft. Zechs is basically the Char-esque character of Wing, a softspoken intelligent strategist with a strong drive to succeed.
Zechs understands the complexities of situations better than most characters, approaching life with a complex duality wherein he blurs the lines between peace and war, love and hate, enemies and allies. Of all the Gundam pilots in Wing, he is the only one who can be called truly wise.
3 Dumb: Andrew Graham
Andrew Graham is the Canadian Gundam pilot in Mobile Suit G Gundam. He pilots the Lumber Gundam, a heavy-duty mech with a pair of axes that rely on raw force rather than finesse or technique.
Andrew dedicated his entire life to avenging the murder of his wife. However, when he finally confronts the man who killed her, the Neo-Canadian pilot realizes he misremembered events and that his wife's death was a reasonable accident. This is possibly the lamest ending to a revenge story in all of mecha anime and basically invalidates years of his life that he spent on a singular crusade for revenge.
2 Genius: Shiro Amada
The protagonist of Mobile Suit Gundam: The 08th MS Team, Shiro is a scholarly and optimistic character who looks at warfare as something to be studied and learned from.
His idealism fades the longer he is involved in conflict--a trait common in soldiers--but he continues to cling to a number of his ideals even after a debilitating injury. While he has extensive training in warfare, it is Shiro's adaptability to ever-changing circumstances that allow him to truly shine.
1 Dumb: Domon Kasshu
Domon is the protagonist of G Gundam and is a bit of an emotional man-baby, constantly erupting in temper tantrums. He is haunted by the specter of his father. It seems often like Domon goes through life looking at each new situation as an opportunity to react impulsively in the worst way possible.
Domon is a surprisingly good Gundam pilot, even operating the God Gundam at the end of the series. However, his victory count is probably quite a bit higher than the number denoting his IQ.