It's all very well saying Warren held him back, but from what? He's in a small minority of fighters with a very successful career.

It's impossible to say how things would have turned-out if they're done different.

For example - Calzaghe was only halted from moving to Lightheavy a few years back through injury. Had that move gone smoothly he would've never achieved the great wins over Lacy and Kessler (which made him).