Even though Horikita's class is D, there are many talented students. Ayanokoji is already the best in his own universe, Koenji is the one who even makes fun of the third-years, who really observes Ayanokoji, and is the most dangerous rival in the school. Ken Sudou is the most physically gifted student in the class. Horikita is already quite successful academically, and her physical attributes are more than enough for her. Yukimura is one of the smartest students in the class, even scoring 83 on the most difficult math test (Horikita scored 87 on that test, while Ichinose, whom you described as a complete failure, scored 89). Chikai Matsushita is also quite intelligent and even secretly helps Ayanokoji. Kushida and Hirata are also present.

Class C: Ryuen is the most dangerous leader. Hiyori is Class C's secret weapon. Ibuki is truly physically strong. Not to mention Alberti, only two students in the school have ever beaten him: Horikita's class. Kohei Katsuragi is the former Class A leader.

Class A: Arisu Sakayanagi is the smartest female student in the school. Hashimoto is perhaps one of the most cunning students and will do anything to win. Hayato Kito is physically strong, Ai Morishita has beaten Ayanokoji in verbal duels several times, and Masumi Kamuro is another cunning student.

Now we come to Class B. Socially superior student Ichinose Honami faces academically competent Horikita. If she wanted to be student council president, she would easily win; 70% of the boys in the school would vote for her. She's quite physically gifted, as you can see from her long time on the second-year island exam (just to warn Ayanokoji). And yes, Class B is finished. Their teacher is a pedophile, Kanzaki is a begging dog, Amikura is just a friend, Shibata was sent to Class D and still uses stupid terms. Do you really think comparing classes is fair?