Fabulous post! Steemit is awesome, and for sure has the potential to overtake Facebook, reddit, etc., and become the dominant platform that people use to share and consume content. You are absolutely right though that there are steps that the site needs to take before it can truly go mainstream. I know the development team is hard at work making improvements. Hopefully this post will help give them inspiration on what directions to take.
I especially want to highlight your first point though about the payment/wallet system. I think this is absolutely crucial for the site to take off to the point that there are millions of users. The average person needs to be able to understand and use the site without feeling overwhelmed, confused, or cheated by the way the payment system works. I know that is what they were going for by the way Steemit was designed, but I think there are still some more tweaks it needs to make before it is totally there.