Personally I would like the ability to mute certain boards.
Like most of us (maybe) I use the "posts since last visit" link daily to refresh the feed but 90% of the posts are for things I am not interested in (Gambling, Bountys, Local etc)
It would be nice to be able to not have these clogging my feed so I could easily find new posts that do interest me.
Also... (this is user generated so would be difficult) Since being back here I have noticed people use the platform a bit like Twitter rather than a discussion forum. What I mean is that there are many posts that have a clickbait title and are just paragraphs of statement obviously copied from elsewhere and usually stating the obvious and not designed to stimulate discussion. It seems their sole purpose is to boost post count and/or hunt for merit.
Just my thoughts but apart from these small issues I am enjoying being back!