^ You should visit some horror movie message boards. You'd be surprised by how people are willing to defend Friday The 13th Part V: A New Beginning or A Nightmare On Elm Street 2: Freddy's Revenge as quality film making.
I think you're right but considering that so few sequels manage to be better than their predecessors, that doesn't seem like the most realistic expectation. Plus, it seems like when people love a movie and then the next one doesn't match it, their dissapointment can make them really come down...
It doesn't take a psychic to know that that's exactly what people will be saying on the internet too. You can generally count on if one movie gets some love, the next one will get panned or outright trashed.