User blog comment:IamJakuhoRaikoben/Chapter 379: Tartarus Arc, Part 3: Underworld King, Review./@comment-5598380-20140404081256/@comment-7418318-20140404132719

Considering how there seems to be no differences at all in the power each of his captured souls puts out, I think Bickslow can only use them as a conduit for his own magic power, rather than using the power the souls had in life. So it's unlikely that capturing Hades' soul would make him stronger... that is if he captrues souls in the first place, rather than the souls working with him of their own will, like Chico=C=Hammit's "friends".