My first choices would be Speed Racer and Star Blazers, but those were syndicated cartoons shown on weekdays after school. It is hard to remember any actual Saturday morning cartoon that I liked as much.
I do not count Looney Toons since those were originally shown in theaters. And I am not counting the live action series that also were shown on Saturday morning.
I guess Superfriends counts here since it was originally just on Saturday mornings for early seasons before going syndicated in later seasons.
Downtime is better than data loss. It was the right decission to make.