SteemIt looks absolutely amazing at first glance, but when you look at it from from a technical and economical perspective on a deeper level, you will find there are still a lot of problems to overcome. Below you will find some of the main reasons why SteemIt is not yet ready for mass adoption (and that we are very early adopters).
Intrinsic value of the STEEM blockchain
Right now the main reason for purchasing the STEEM token is because of speculation (trading). To make the STEEM market more liquid and eventually more stable, potential investors need more long-term value while holding STEEM. The ultimate goal is to make the STEEM blockchain so valueable that even venture capitalists will be interested in investing, without specifically wanting to use to social media platform (SteemIt). A year ago i read Steemit's Evil Plan for Cryptocurrency World Domination which gives some more insight on the future of the STEEM blockchain.
Ease of use
This is one of the main obstacles to overcome. Although it's currently not the worst, there is a lot that could be improved. The user interface for steemit.com specifically could use a lot of upgrades. Extensive, easy to access help and preferably extensive video tutorials should be available too at some point.
Then the biggest problem: the difficulty of cryptocurrencies. This technology is so new that it isn't anywhere near user friendly enough to reach mass adoption. Imagine having to teach your mom how to exchange STEEM into Bitcoin and then into fiat. The procedure is cumbersome and there is a large potential for errors.
After 7 days your content can't earn money anymore
This current implementation is extremely harsh to content creators. Imagine going trough the process of writing a book and then when you are finally ready to publish it, the publisher will only pay you based on the sales of the first 7 days. That's extremely unreasonable and many people wouldn't want to publish their content anymore. Although most publications on SteemIt won't quite require 100s of hours of work, content creators will likely deliver a lot lower quality because of this extreme limitation on SteemIt currently.
Most user are powerless
With the current implementation, 100s and 100s of users have less power than 1 person with a lot of STEEM POWER. This is the opposite of the preferred behavior. The ideal situation is that 100s of people are exptected to be much more reliable in curating content properly than just 1 person.
On top of that imagine the following situation: A group of wealthy malicious users joins SteemIt, their posts will make 10s or even 100s of times more than average posts and because the group simply owns too much power, the current majority that is online at that moment will be unable to curate it (in fact what currently happens is that everyone will upvote it to get curation rewards from it, rather than attempt to curate the content properly and flag it). This group can dominate the network, decide what content earns what, what content should be trending, which users should get lower or higher reputations and so on. To a certain extend this is already happening on a daily basis. Currently you see a lot of popular users earn ridiculous amounts of money on content that is sometimes far below the expected quality and there is almost nothing the majority of users can do about it.