I think he past his prime a few years ago.
It does not take much, probably less than a 1% loss in ability that makes a world elite into a journeyman. He is still good, but he is not what he was.
He looked fast because Rios is slow. I noticed not the speed but the lacks of power and sting in his punches.
He still seems to have the speed when he needs it but overall his combo's seem to have slowed a bit, just a bit and he's still faster than most out there IMO.
he was spectacular before he got nuked by jmm last time they fought, the venom was back and really stinging jmm, in fact jmm was breathing hard in the mouth and was already ready to go on the next 2-3 rounds when luck opened and gave jmm the window to drop that unforgettable bomb...
i must presume pacs performance against rios was due to his BS training in RP
I think he has slowed down marginally from his peak, Cotto, Delahoya. Thoughts?