1) Teammates - the '05-'06 Cup team had a strong supporting cast -- Brindy and Cole in their prime, Recchi, Weight, a young Andrew Ladd, etc. Since that time, he rarely has enjoyed such skilled players up and down the lineup. A case of simple $$$, I suppose.
Seeing what Sid the Kid is doing this year, and seeing what he's done over the course of his career, it's clear he's the best player in the league and Pitt's superstar. Our own superstar, Eric Staal, is no slouch, but something is keeping him back from joining Crosby as one of the top 5 players in this league. What is it? He's got the physical tools, experience, hockey sense, and overall skills. The year we won the Cup he was an absolute beast. Why, then, can't he shine year-in, year-out?
2) Coaching - the Lavi system was more attuned to his offensive mind set. We've all seen Staal take some shifts off over the years defensively, although since gaining the C he's been much stronger in that category. Still, his numbers were never better than under Lavi. Also, Lavi regularly double-shifted Staal, something we're not seeing this year on a regular basis.
3) Attitude - maybe it's the market he plays in, maybe it's his teammates, but Staal just doesn't seem to have that burning desire to absolutely go balls-out every single night in pursuit of the Cup. On nights his young team is over-matched, he seems to disappear somewhat and become one-dimensional.
4) Physicality - Staal is a big boy, but I rarely see him lay a bone-crusher on a player to jack his team up when they don't have jump. Talking on the bench is one thing; banging in front of the crease and mixing it up after the whistle is another. Crosby regularly wails on people, and if he's on the ice when someone takes liberties with a teammate, no matter who it is, Crosby is one of the first in trying to start something. Staal often glides over and just starts yapping. If he became more physical, that would filter down through the ranks.
Interested in other people's thoughts as to what could push Staal over the top...