Everybody's talking about what kind of legacy Brock has left behind in MMA. At the end of the day Brock Lesnar was simply a better version of Kimbo Slice, both fighters were out of their depth in MMA, but Brock faired slightly better. Brock's last 3 fights have shown how out depth he was in the UFC, even when he beat Carwin he got completely destroyed on his feet, and had he been facing a more disciplined fighter in cardio he would have lost that fight. His last fight against Overeem truly showed how out of depth he was, sure Brock had the size, but even with his huge size he looked like a little kid in that octagon, someone out of their depth, and someone who did not belong in that cage. Had it not been for the UFC's hype train of Brock, everybody would have been coming out and saying what a major mismatch that fight was, especially considering Brock's previous fight and how badly he was destroyed.
Brock's aura to MMA came outside the octagon action, and that's where his real legacy comes from, but when it came to actual MMA action, he didn't bring anything special inside the octagon. At the end of the day, I don't think Brock will be remembered as a great MMA fighter.