They have weight classes for reasons indeed, this matters when fighters are evenly skilled to make things more fair.
Pudz agaisnt GSP is not a skilled fighter vs a skilled fighter however, and put pudz vs another heavyweight and he'd get murked. Guys like Carwin and brock are much stronger than him interms of grappling and fighting, doubt they care they cant pull and anvil as far though.
Against cain, gsp would get smashed as he is bigger and stronger and also skilled. Prob plenty of 205's as well being that gsp relies on a big strength advantage at his weight class.
