@ekitcho, I like how you're thinking! I don't wonder if it might be confusing to to be able to access a raw tag versus filtering your feed through a tag. But you're right, we need to get specific. Maybe it's a silly one but what about..

1. Being able to view other people's feeds?
   There are lots of friends whom I really like on steemit...and I can view their following list, but wouldn't it be sweet to drop in on someone elses feed for a moment?

2. average length of comments
   I don't know what level you could do this on, it might have to be onchain, or pre-processed by a server running steemd...but that would be pretty cool to filter a feed by posts that have longer average comments

3. multiple $$$ levels of trending?
   what if you isolated a few levels of trending, like you could click on $5, $25, $125, $500+, and it would show you all the 'trending' posts that are around that reward level. part of the problem now it seems is that you can get whatever support you garner from your followers, but after that, your sources of fresh eyes are either resteems, or trending. Maybe this would help some of those smaller and inbetween posts get some fresh eyes, and it would be a great place for curators to scout too

4. sort by upvote and comment percentages?
   so posts that have a really high percentage of upvotes/comments per views might show up higher in this sort

just a few thoughts