I actually had a friend say that she didn't like Columbo because you knew who did it as soon as you saw the guest star. Yes, and. It's not supposed to be a who-dunnit. We do know right away, and so does Columbo. Sherlock Holmes used science to find clues to find the culprit. Columbo a master of human nature, knows right away and just pecks, and pecks until the moment when the culprit knows that Columo knows, then the jig is up.
Some of my favorite things of the show are #1: We never learn his first name. #2 The time the guilty "help" Columbo solve his crime, furtering the temperature of water they are in. #3 We never see the perverbial wife. She could be his Watson, or a divice he uses to further his appearence of ineptitude. #4 The car and the coat.
Monk is good but there is no one like Columbo.