There are few disputes about which teams are the best teams and the worst teams of all times, so long as you aren’t that particular about the rankings within those teams. Wins pretty much answer the question: good teams have a lot and bad teams have few. At the margins, you can argue that some teams were really lucky or unlucky and modify the metrics, but the Parcells Theorem (‘You are what your record says you are’) admits few exceptions.
But determining the most mediocre teams of all time is not quite so easy. You can start with the teams who finished within one game of .