No he really hasn't. He looks the same in every fight. I don't buy this he wasn't training full time thing. If he wasn't training full time he's an idiot and no amount of training will overcome that.
You can be any sort of negative non-fan, it doesn't change facts. GSP and his trainers at Golden Glory have stated that Gegard just "messes around" and doesn't take training seriously. Then he came out in 2012 and said he is training legitimately for the first time. He event went as far as saying he had no idea how hard an MMA training camp was until now.
No matter how much you hate him, he still was the Dream MW, Dream LHW, and Strikeforce LHW with a K1 win over Kyotaro the K1 HW champion. And he's only 27.