I read that Lennon called Reelin in the Years the best rock and roll song he ever heard.
People overreact to the lyrics of Imagine. Lennon didn't believe in that shit. Like with pretty much every Beatles song, and most other pop songs, the lyrics came last. He just came up with some words that fit the melody he had already written.
I do agree with mocking the cheese ball lyrics. He was just playing to his audience though.