He would be a Top 5 guy for sure in WW (assuming he could make weight) and probably at MW too. The guy was so far ahead of his time in terms of developing a well-rounded base for MMA. He had deadly hands, very underrated take downs (took Matt Lindland down twice in their championship fight), excellent cardio, and the best overall ground game 185 saw until Maia and Jacare showed up, IMO. The problem he had was he was just too old and inactive to stay relevant once the new breed of fighters started showing up. That being said, he held his own at 205 with Chuck and Rampage and I thought he beat Hendo in their rematch so it's not like he didn't have his moments, but overall he was just born a decade too early for us to really know what he was capable of by fighting MW's like Franklin, Anderson, Belfort, etc. when he was in his athletic prime.
By the by, if you're looking to watch a classic event from yesteryear that is often overlooked in terms of entertainment value, check out UFC 37. The main event was Busta/Lindland and it was a showcase of just how good Busta was. It also highlights how terrible reffing was back in the day, how ridiculous Baroni was, and you get to see Robbie Lawler's UFC debut at the ripe old age of 19 (man, he was a lot skinnier back then).