I never thought that intelligence was a requirement to become a teacher, and if you look at Hogwarts it certainly wasn't an attribute Dumbledore looked for in his professors. As you said though, Neville was a war hero, and wizarding Britain seems to discriminate positively when it comes to celebs. Either way, he was meant to be pretty good at Herbology, if not the prodigy that many fics seem to portray him as. So, even if he wasn't a great student in general, being good at one subject, well liked, and not a blood purist would probably be enough to get him hired by McGonagall. As for the forgetfulness, well people can change, but it would hardly be noticeable next to some of the other teachers' unique traits.

 

Making threads with titles that tell people what the discussion is about?

 

The thread's about something I just realized bothers me.

 

Hahaha...