IMO, the two biggest hurdles Crosby faces are...
1. The NHL's hard-sell of him
There's a saying in marketing - "people love to shop but hate being sold to." And the same rings true whenever a corporation or the media tries to "sell the public." Since day 1, the NHL has used every ounce of its power to oversell Crosby to the masses in hopes of gaining popularity. To the longtime, die-hard fans, this tactic has unfairly backfired and is most responsible for their dislike of Crosby IMO.
It's not jealously or envy (I'm sure to a certain extent fans are jealous Crosby doesn't play for their team) but it's the non-stop Crosby narrative that wears on fans who follow the game religiously. I compare it to a radio station playing the same song over and over and over. At some point fatigue sets in, followed by disgust. IMO, if the NHL (and media) wasn't blatantly so "Pro-Crosby", the fans would fight to give him his just due.
2. The eye test
This is the biggest hurdle IMO. I insist that Crosby is a hockey player's hockey player. The dedication, the non-stop practice, the ability to face adversity and never rattle, the pressures that come with being "the face" of the NHL and always keeping your nose clean. The ability to lead by example night after night, shift after shift. These are the things that make Crosby incredibly special.
Yes, Sid is extremely talented, let's be honest. But he doesn't fly at top speed like McDavid. He doesn't take blistering shots like Ovechkin or Laine. He doesn't dangle and make your chin drop like Kane or Malkin. He doesn't blast people through the boards like Burns or Byfuglien. I've been watching Crosby since day one and he's rarely "wowed" me. He's made some awesome plays and shots but he doesn't do it with the same flair as a Kane, Malkin, McDavid... let alone legends like Lemieux, Jagr, Orr and Bure, who "wowed" you every game.
Crosby does all the things that result in wins and making his team better - things that don't always play well on YouTube. The more I've watched Sid over the years, the more I've learned to appreciate how great he really is - but I'd take $100 out of my pocket and pay to watch Karlsson or McDavid play before I did Crosby.