It helps for me to make a distinction between two kinds of alternate history: divergent alternate history where history diverges and never returns, and parallel alternate history where historical figures and patterns emerge.
They're both awesome, but for completely different reasons.
I consider the second a joke, but then comedy can be fun. (A big fan of
Airplane and the
Marx Brothers movies myself).
Edit: perhaps that came across as too harsh. To clarify, I consider the notion of history being on some sort of rails so that people like Napoleon and Hitler and John F Kennedy keep showing up in spite of major PODs to be fantasy, not alternate history, but that doesn't mean I can't enjoy a story set in such a setting. I
would read a story set in 1970 in a world where the (Eastern) Roman empire never fell and now threatens western Europe, south America is inhabited by sentient bird-like dinosaurs, and Richard Nixon is still president of the United States.