I don't hate the episode, but even despite my contrarianism I have to admit I've been brought around to agree that it was a very bad episode for the universe even if it was an OK episode internally. It's easy to forget if you are young and you've never lived in a world where Simpson's seasons 1-7 or so are all there was in the world, but the Simpson's used to actually have a universe, rules, characters that were more than walking stereotypes, and even a bit of capacity for lasting consequences, and thus, a capacity for drama that the modern "cartoony" (in the bad sense) version has a very hard time sustaining.
If you were raised in the modern era, you can get the reverse effect that some of us oldster's describe by going back and watching Season 1 in order. It is not the best season, but it was already showing a lot of the promise that would manifest a couple of seasons later, and in so many ways you'll find it is just a different show, even more clearly than if you go a couple of seasons later. (And it does have my favorite Halloween episode. I have to admit I haven't seen them all, and there were certainly some other good ones, but when it comes down to it, it is hard to beat a dramatic reading of The Raven. There's a reason this became a tradition and not just a one-off.)
It’s not that the episode itself is all that bad in and of itself. Fans think of it as a turning point in tone (changing the long time Skinner character). Think of it as the beginning of the very long and steep decline.
