Any suggestions for improvements?

Many. Some, if not most, have already been implemented, I went back through my blog posts and found that the UI has indeed improved over the months and during my hiatus. Comment nesting depth has increased, for example, I like that. Blocking has been implemented, a very important feature that circumvents the calls for centralized censorship of trolls.

Other implementations will take years, it seems.

PMs for example. How can that simple, fundamental function not be working yet?

Or a profile page. I concede that the profile pics and "about" fields are a step in the right direction, but a living, breathing profile page à la MySpace, preferably even with editable CSS, could be more than just awesome. It could be a business card. A sorted index of your own or other's best blog posts. A short introduction, and invitation to press "follow". A collection of songs or artwork for musicians and artists. It is my own personal conspiracy theory that MySpace was destroyed on purpose, because no platform ever managed to connect vertically and horizontally as much as MySpace did. As an amateur musician and artist, I (and I believe many others) found friends, collabos, gigs, "fans" and support from popular musicians in a natural, organic manner completely unlike Soundcloud or Facebook, and I blame the MySpace profile page and its guestbook. "Thanks for the friendship!" Let steemit fill that vacuum: MySteem!

And, most of all, a customizable feed filter. With boolean operators for tags, or thresholds for payouts/number of votes and the like. Between "created" and "trending" so many posts are lost when you're not online 24/7 that it is no wonder that curation becomes a pain in the lower back, and it doesn't make sense to painstakingly switch between tags manually. Let me assemble a list of tags I want to keep an eye on, just as I can subscribe to subs on reddit and create my own, personal /r/all feed. Let me manage multiple of these list, because I have many interests. "fandom" includes "starwars" and "agot" and "asoiaf", "retro" consists of "gameboy" and "c64" and "chiptune OR chiptunes OR chipmusic", "conspiracy" includes "conspiracy" and "investigate911" and "debunking" and "NOT flatearth" and so on.

Steemshovel was a step in the right direction, but it seems the project went offline again. I'm happy to see that bbchain.com and asksteemit.com and so many other external apps and blockchain browsers are thriving, so I have hopes for the future that steemit.com itself will implement the best of these features in the next years, or that browser extensions, or even dedicated standalone steem browsers (like piston) will supply for such and similar demands :)