I'm sorry, but it's not really debatable. Crosby's 10-11 season blew everything else away. He dominated every single night and was playing the most complete hockey anyone in this era has. No one else has showed that dominance in both goal scoring and playmaking.
You want to talk about linemates so much, in Geno's 11-12 season he had Kunitz and Neal. Sid had Kunitz and Dupuis.
I'm sorry you don't think Sid's goals were as "pretty" as Geno's, but that means nothing in terms of domination.
+Geno on PP
Geno didn't have Sid and Letang for most of the 2011-2012 season, in case you forget.
And please, i love Sid but don't blow that half season of him out of proportions.
He was great but he was not dominant to the point he could dangle around everyone or consistently score highlights goals.
That was not the sort of dominance you could see with Mario, Jagr or even, yes even Geno during some of his big runs.
It's not only about points, i'm talking mostly about the dominance in term of puck possession and ability to skate through the opposite defenders like they were nothing.
Sid is a fantastic passer and has a wonderful eye-coordination speed and vision but there are players who when they are at their best looks/are more dominant and harder to stop, that's all.