The early UFC matches were set up to show the dominance of BJJ, specifically Gracie Jiu Jitsu. None of the guys participating knew how to defeat that style.
Once high level wrestlers started learning BJJ it was a completely different sport. Guys like Matt Hughes and Tito Ortiz changed the game. Even when Chuck Liddell was dominant it was his wrestling ability and knowledge of BJJ defense that made it possible for him to stay on his feet or get up quickly so that he could end it with punches.
GSP is another elite wrestler with very strong knowledge of BJJ who was on a whole other level in the UFC as well.
Most the guys who get their name thrown around as "greatest pound 4 pound" fighter in MMA aren't one dimensional at all, all of them have some sort of striking AND grappling background to.
I personally think wrestling is king if all things are equal if looking at just focusing on one style. Would be able to keep striking guys on their back, would be able to prevent BJJ takedowns. Just such a good strong foundation for MMA.
Quite a few high level wrestlers who were essentially one dimensional have had some serious success too. (Ben Askren the most recent)