Well... Steem's problem IMO isn't UI/UX, a good mobile app (eSteem already exists), or any of the above.
It is bots and the aggregation of power.
Bots
Automatic upvotes are everywhere. People are paying for these, giving them away in exchange for pledging support, etc. NONE of this actually adds to the value of Steem or leads to more unique content creation. It incentivizes gaming the system. Also, my posts are starting to be plagued by ridiculous bots. There is a bot for this, a bot for that, a bot for EVERYTHING. It's frustrating and annoying when you spend time on a post only to see it get 2 comments for random low rep person and their bot.
Aggregation of Power
There are too few people with too much power here. To make money on a post, you need to pander to the whales. To become a witness, you need to pander to the whales. The same people make money consistently and they don't do so because of consistent good quality posts. I've seen some of the best, most genuine content in posts that receive less than $1.
This all really came to light when I became witness for a week. I started by campaigning to my home group @steemitbc. But, I quickly realized that was a waste of time. I looked for a few whale/dolphin friends and before I knew it I was top 100. I brought this concern up when discussing DPOS with a certain high up in the block.one organization and they agreed 100%. In fact, they said "that's why I didn't invest in Steemit."
So, in conclusion, I think THESE are the problems that need to be addressed... not some pretty UX/UI improvements. I hope @steemitblog or @ned see this, but I'm not sure they will.
That being said, I'm still a happy Steemian and blog here multiple times a week.
Cheers and Steem on!