I have plenty of personal favorites, including Phil Hartman, but there was a time when Murphy WAS SNL, and then left to become the top box office draw. We've had SNL members become the focus of the show, but not to the point that Murphy was. And plenty have had success in Hollywood, but none were #1 like Eddie Murphy.
I wonder how much of his noteriety he owes to the night they did the whole show with Nightline interruptions announcing Buckwheat was shot, dead, not dead, dead, etc. From my personal point of view, that is what made him stand out from the rest (in terms of recognition and name remembrance, not talent which he had far ahead of the rest of the cast).
But what do I know? I liked Pluto Nash.