There are some things that could be done which I think will really help Steemit grow, but Steem Inc is working hard at releasing a new version with support for communities. That will be very interesting.

What I feel is largely overlooked is the necessity of multi-language support.
Both the language you see the site in, but also only seeing posts you can understand.
I am not interested in posts in languages I don't understand or can't even read, but they still keep cluttering up my timeline.

And the sign-up process needs to be improved. I tried giving my wife an account for over a month, and finally managed with the help of someone else. The normal process just doesn't work as it should.