I'd say it's the opposite. Today's fighters weight jump so much that divisional rankings don't mean what they should, and 'pound for pound' greatness is thrown around so much and given prominence by Ring mag and other media that it's become misunderstood as some sort of earned accomplishment. Because fighters of the same weight are competing for divisional supremacy, divisional rankings should strictly be based on 'resume' at that division, not ability. But because a flyweight can't fight a middleweight pound for pound is only comparative, necessarily subjective evaluation of ability or who beats who regardless of weight, with resume not being highly significant.
A boxer's skill level and accomplishments regardless of weightclass and size. But nowadays it means who do I like more, who is from my little part of the globe, who is fighting for the 'right' promoter and who has the 'right' skin color. It is all bull these days and close to useless.
My definition of p4p is basically the same as my definition for predicting fights: Defensive skill, offensive technique and timing, boxing IQ or ring generalship, dominance in wins, success vs a variety of styles, chin. Who's the better boxer above and beyond mere cv. People who think p4p is primarily based on accomplishments (and rate guys like Bradley, Wlad, or Froch highly).. tend to be horrible at picking fights!