One could argue that Calzaghe is the best fighter Hopkins has fought since RJJ.

In fact look at it this way.

Tarver was big and strong, but lethargic and mentally impotent.
Oscar was classy and fast, but undersized.
Trinidad was nowhere near the puncher he was at 147, undersized.
Winky was fighting 3 divisions North of his best weight!

The two fighters who matched Bernard for size and physicality were Jones Jr and Taylor.

Calzaghe is of a similar height, good reach, good chin, fought at Super Middle his entire career, deals with physicality well, great stamina.