For me, it's Crosby's sometimes unwillingness to shoot the puck. There's more than a few occasions where he'll have a clear shot or clear lane to the net, but will look for the pass to either a winger with stone hands or a trailing defenseman who ends up shooting the puck into the goalie's chest.
I'd like him to take the shots that are available to him more. I understand he'll never be like Ovechkin and shoot every time he comes over the blue line, but I'd just look to see Sid shoot in the instances where he's got a legitimate chance to score.
When Sid scored 51 goals and followed it up with 32 goals in 41 games before Steckel brained him, he was doing exactly that. He was shooting any chance he got. I prefer that Sid.