Many people who enjoy Cannabis on a regular basis, may have not always loved the portrayal of Otto. Since he is the only character on the show to partake regularly, he has long been a somewhat problematic character. He is able to fall for every single different stereotype people have about stoners, simultaneously. Since as we all know many people who enjoy weed regularly and: haven't been in a failed band, are not routinely outsmarted by elementary school children, or take other psychedelic drugs. The character isn't exactly indicative of the larger population. He isn't as problematic as Apu, but, is one example of some of the negative stereotypes about people who use Cannabis that we have to start addressing. It would be as if the only person on the Simpsons who drank alcohol was also Barney.
Otto Mann also made the promo poster they made
Of course you should judge for yourself. The Simpsons is not as great as it once was but the Halloween special is still worth checking out.