I've also thought that more filters in the feed/browsing interfaces could be good. Such as only display content from users within certain reputation score ranges, only display content that's been voted (or as you're trying to get the term to be, "upsteemed"!) on x amount of times, hide resteems, only display content with x amount of comments or more, hide posts of less than 100 words, and so on.
Just ways to sift out some of the slew of low-effort posts via the front-end. I'm really hoping something comes along in a future update for both the front-end and the reward system that penalizes particularly poor content - such as downvote/flagging being free but requiring approval (unrealistic given the scale that Steemit will grow to and the amount of human effort required to do something like this). But just some way to raise the bar a little bit. I wrote an extensive reply on another post that had some of the same points. I'll link below as I'd love to hear your thoughts too: