You say Gai is a good sensei but yet say that Kakashi is a bad one. I don't get it, I have always thought both Senseis to be equal.
As a sensei isn't your responsibility to teach/improve the abilities of the whole team. What exactly did Gai do with Neji and Tenten again? Did he make them run 500 laps around the black top while he paid attention to Lee only. Not sure how you are saying Kakashi could've been better considering the circumstances.
Sakura wasn't adaptable to his teaching style so why bother teaching a fodder who was more into love than ninjutsu. This was not his fault. He gave Naruto in the hands of Jiraiya because honestly though he knew how to create the Rasengan, Naruto bored him to death with his simplicity.
Don't tell me he didn't do anything for Sasuke and one more thing failing to stop Sasuke at his path of Revenge isn't his fault either because Saduke was hellbent on leaving to get power from Orochimaru.
What I find very ironic is that people praise Gai so much yet neglect Kakashi. Does Gai's team or any other team have the necessary teamwork skills.
Oh I forgot the dude was there for Naruto in Part 2 when he needed him the most.
Well, excepting stuff to do with Sasuke turning evil, specifically...
I don't even blame Kakashi for Sakura. She specialized almost entirely in things that were better learned elsewhere.
Gai training Lee runs on the same logic as Sasuke training Kakashi; they specialize in the same areas, so it makes sense. Neji's a genius and unless his trainer is a Hyuuga, no one can probably train him better than he can train himself; we don't know anything about Tenten but she was arguably the best rookie kunoichi of Konoha during the Chuunin exams (her shurikenjutsu excels, Hinata is probably in second place with her taijutsu). So there's no reason to say Gai was anything less than perfectly competent.
As far as we know, Team Gai was pretty good at cooperation. We know Neji and Lee respected each other; Tenten gets along fine with them even if she gets frustrated by their rivalry. There wasn't some inferiority complex dynamic going on like there was in Team 7. When Lee was feeling inferior, Gai resolved it. As a sensei, Kakashi should have been able to perceive such things better and resolve them accordingly. Team Gai did perfectly fine during the Chuunin exams.
Gai instilled a very important lesson into Lee about protecting one's friends that's going to stay with him forever. Whatever Sasuke learned about things like friendship, he probably learned from Naruto, except for that one moment in like the first couple of chapters in the manga.
In the last bit of the manga Kakashi has to remind himself to keep pushing along with his team against Kaguya. Why in the hell does Kakashi have confidence issues? Gai would have been in there, no hesitation.
They're both good sensei, but Gai is great.