One thing that I think will be a barrier to entry is that the system has a lot of moving parts, so it will be difficult for people to understand.
At whatever point in time the goal is mass adoption, steem needs to focus on not trying to explain EVERYTHING about the platform, and just stick to clearly communicating the core benefits. "Social media with incentives."
It would also help to have content creators with large existing fanbases migrate over to steem.
Facebook is also quite difficult. log onto facebook and try and see it through the eyes of a newbie, theres heaps going on that is far more overwhelming than the initial steemit experience. To me; signing up, up-voting and creating content seems very simple here...
I Agree @maxip i didnt find steemit all to difficult, especially when someone allready has social media or blogging exprience i think users will feel at home pretty fast. It will definitely help if some big content creators would join @jbriggs and im sure it doesnt take long before the hope on the ''Steemtrain''