Going by forums I frequent and reddit, the story is seen as a huge hindrance for even people who otherwise enjoy the game. Many do not actually dislike the story itself, but the myriad of fetch quests and content restrictions imposed on their progression. I've read plenty of posts where people finished 2.0 yet ultimately quit once they realized they still had another 100 odd quests left to slog through. Sadly, the only solution that wouldn't otherwise affect financial costs in relation to creating more content is a jump potion.
Another semi-common complaint is how slow the GCD iis whilst leveling. You unlock skills at suck a gradual pace, some people just cannot keep interest, especially given the aforementioned MSQ further slowing them down.
I'd say those two are the biggest hurdle for new players. More so those coming from other MMOs.
