Just looking at some stats.
Kallis averages 55 with the bat, Imran 22 with the ball (better than both Wasim and Waqar). Yet neither player features all that often in World XIs. Can't figure this out, other than to think that if they weren't allrounders they would have been judged on their primary skill alone and would so have been regarded much higher.
Imran averages a run more per wicket than Glenn McGrath with the ball yet would offer 60 runs a match more with the bat. Yet McGrath is in more ATG teams. And Kallis averages more than Tendulkar with the bat despite being vastly superior as a 5th option. Yet Tendulkar is in more ATG teams. WTF.