People kept using size as an excuse when Brock beat Randy and Mir. Yet when he lost to Cain his size didn't matter? Its skill that prevails not size. Same thing happened with fedor tonight.
You should try rolling in a BJJ class with people who weigh in excess of 200lbs. Even the noobies cause difficulties from their sheer weight. After several rounds it's exhausting. Now imagine Fedor with a 285 pounder throwing bombs on you. The fact that he survived was a feat on its own. Unfortunately it's not 1993 anymore. Most fighters are very well rounded now.
When the bigger guy doesn't have great skills (Brock) and the smaller guy has better skills - then NO, size doesn't matter!
But when you are 230 lbs heavy and you have a 285 lbs Brazilian Black Belt mounting you, dropping bombs and going for submissions - then YES, size matters!
Truth! How did Fedor fight off the RNC, arm triangle, and knee bar. It looked tight! Man if only there was a third round. Fedor had the first round then he went for broke in the opening 2nd round and got taken down. It was the beginning of the end and perhaps the end of "The Emperor's" reign.
It's all on Overeem now!