If a time machine could bring a fighter back in time two years to face themselves two years ago, which current fighters do you think would beat that version of themselves two years ago and which would lose to their former self. Then you can consider how about 5 years ago? or 10 Years ago? The sky is the limit. Strangely, I think Frank Mir whom just beat Todd duffee, could probably beat the Frank Mir who was in the middle of a four fight losing streak back in 2013. Current Dan Henderson would probably be a very even match for his former self of two years ago.
Pre Zuffa Tito was at the height of his career....but I must say, he is a far better striker now and probably has enough defensive wrestling to keep it standing. So I think current Tito beats pre - zuffa Tito.
The Machida that was absolutely ripped and schooled Munoz and Mousasi would obliterate the current soft and slow Machida. It's interesting how quickly a fighter can fall off the cliff. In boxing, it's always been said that when a fighter is advanced in years, he can become "old" at any point, almost instantly. The same holds true for MMA. Current Ronda would smash the Ronda from 2 years ago. Her striking has gotten exponentially better. Current Vitor would get savaged by the Vitor from 2 years ago.