Riggins was (allegedly) a party animal whereas Alstott was a VERY hard working guy. I definitely think Alstott would pull better numbers but in terms of raw talent I would think number 44 had the edge. I loved how Mike got his SB ring and even scored the first TD of the game back then.
I'd be surprised if they didn't try and sign some retreat to shore up the depth, but still am hopeful that at least a good chunk of the carries will go to Steele.