IO9 spends a few minutes discussing why “Threequels”, movie series end up becoming trilogy, typically end up having the third movie being rubbish. Â Typically this is true, their examples include Spider-Man 3, Aliens 3, SuperMan 3, etc….
They’ve really thought about this and have some good hints, tips, and suggestions for any aspiring film makers.
io9 – Why Are Movie Threequels Always So Terrible? – Movies.