Dune I can give a pass to because Frank Herbert originally wrote it as a trilogy and combined it into one book. It has pretty clear chunks breaking it up. They absolutely should have been better about advertising what it was, but it’s hard to cover all that content succinctly

Wicked however is based off a 2 hour and 45 minute Broadway show with a 15 minute intermission. There is no good reason that a movie that can have tighter transistons, faster costume changes, and no reused cast should be longer than the Broadway show. Let alone twice as long and spread over multiple films