You know, I thought Onizuka was kind of a douche at the beginning, but honestly, apart from his sex obsession, he's a great guy with his heart in the right place. I think he will be a good teacher because he can understand the delinquents well. I also like how he's growing and leaving the high school girls alone.
I'm starting to get why people like this manga! It's just about a tough guy who has a great heart but who only knows how to solve things with fights. Very funny and the art is great too.
Also, I feel awful for the other teacher, imagine going to a job interview only to have your harrasser be your boss.