When was his day? He's younger than GSP, Robbie Lawler, Maia and many others who fought around the same time. Due to fighting lower their guys he's recieved almost no damage until his last three fights in the UFC. What big names or top five/ten guys do you think he could've beat knowing how he did in his last three?
Well, he did beat Lawler for a start. He looked good against Maia, who was an awful matchup, scoring 4 takedowns against a guy who had only been taken down 3 times previously in all of his WW fights combined. And the Masvidal finish was a 1/1000 occurrence.
He will forever remain a 'what if'. He had a solid career, but never proved he was able to lay claim to being at the top of the heap. On the other hand, his two losses didn't expose him as some fraud.