Maybe we should pause and recall the early days of UFC and the like. No weight classes, not so many rules, lots of carnage.
As for Lesnar, if you watch him, he's actually pretty goofy. A good wrestler, certainly, but if he was the same size as his opponents, his shortcomings would be more evident. As it is, he's just too big for most guys to handle. He's learning how to play the game quickly though.
But at the end of the day, he's an [censored].
I want GSP and Machida to fight. GSP comes into a fight at about 190 anyway, and Lyoto is a 'smallish' 205.