With regard to the complexity:
I haven't used it personally, but there are some I follow who have and said good things about it. If I am correct, Jon based the training on his own experience learning Steem and Steemit. If I am right, there may be more advanced training he adds when he learns more.
There are some tutorials out there. For instance @jongolson has @steemsavvy.
Mobile phones are what all younger people use for all communication. Even those a little grey around the edges and long in the tooth use their phone a lot. @eSteem works for a quick snapshot and a few words, or for sharing an article or other content. It still has some challenges, like if you try to edit a post on the iPhone, it is almost impossible. The title block is locked in place on the screen and the keyboard pops up and covers almost everything else on the screen except a couple of lines.
Searching for content:
This is one that really irritates me. It would be nice to search for something and get relevant results. It would be much more attractive and keep more new people around if they could find relevant content they are interested in outside of looking through tags.
I have expanded on some of this in my latest post. I have been using computers for decades, so I adapt fairly easily to new technology, but you can see how Steem would look scary to many. For some it has to be really simple and I am not sure how possible that is. That said, I see a lot of less techie people managing fine here. We need their feedback on how they cope.