The only problem that I've found using heavier or larger gloves for a lot of pad work or heavy bag work is that it also throws off your timing and balance. If you're used to your hands and arms traveling at a certain speed and weighted down by a certain weight, then your body adjusts to compensate. When that changes it takes some getting used to.
Calzaghe kept using the expression 'sit on my punches' in regards to what he was going to do in the Hopkins fight. Expect another slap-down by Joe. Leapords dont change their spots.