I am on yellow so, I will word this carefully.
According to Rogan on JRE podcast, he said RJJ was on "MEXICAN SUPPLEMENTS." I cannot agree nor verify said results but he fought @ HW and won a belt. Not the actual HW champ but one of the sanctioning body belts. Still pretty epic in his win over John Ruiz.
A return to HW, RJJ looked rough. Speed was lost. Timing was off. Maybe he got old. Hands down in the rematch and Tarver slept him.
Similarly, Fedor fighting Choi/Coleman/Monson/Linland among other cans is the same sort of fuckery that pisses off a die hard fan. I am a FIGHT FAN 1st > all else. I am pissed GSP ducked Anderson/TW/Count/Hendricks rematch too. As a fight fan, I want these super fights but, as a GSP fan, I am happy he didn't end up looking like Franklin/reconstructive facial surgery. Prime Andy was scary.
Point is, a fighters prime is fragile like a woman's SMV/Aesthetics. Once its gone, its game over, and all the wishing wont bring it back.