UFC Featherweight was just WEC so you can count his WEC fights as well. For me I don't put much stock in what happens after a fighter falls off a bit. One thing to note is he stipped throwing leg kicks so at the very least he wasn't able to fight the same way. Also even if he didn't get too old, the game is always evolving. When he was on his big winstreak his style was enough to handle anyone he encountered. Just because people came around with the skills to beat him doesn't mean we should discount what he did over the course of 10 years.
I think Aldo was a bit lucky not to have had to face any really good strikers before Conor but hey it's not his fault there weren't any around. Also if they were around before when Aldo was younger maybe Aldo could have adapted his game, his style worked great for what he had to face. Good striking and great takedown defense.