Kessler could end up with a better resume than Calzaghe after the super 6, but it'd probably take a couple more wins to solidify. I mean just cos Joe beat him once dont mean that his resume is better. For example RJJ beat BHOP as easily as Joe beat Kess but a lot of people would say Bhop's resume and career is more impressive due to better opposition fought.
If Kess went thru undefeated then he would have to be seen as nearly having as good a resume as Joe. Then if he defeated say Bute and Pavlik for arguments sake it'd be bloody hard for even the keenest Calzaghe fan to say Kess didnt have a better Resume. He'd be 48-1 with potentially wins over Beyer, Mundine, Andrade, Ward, then maybe Taylor, Dirrel, Abraham, Froch, Bute, Pavlik. Of course one of those would be missing.