I'm a fan towards the movement of a more modern aesthetic using more padding and illustrations. I'm liking some of the things happening on the frontpage of the website.
There were a few UX/UI decisions that I'm finding to be cumbersome.
The sidebar is a bit large, distracting, and I've lost the ability to easily accomplish key functions (check notifications, make new discussion, and search).
The profile pages are a step backwards, I actually really loved the layout of the previous iteration.
The colors still need a bit of work. It's too low contrast at the moment, making the site difficult to read. And the fonts just aren't doing it in some areas (like the buttons, or the mash up between solid sans-serif titles and the very curly serif description). A few tweaks in font choices could elevate it to another level.
The new editor looks better, and improves upon the last by adding quick buttons for Markdown that I couldn't recall. That said, it does need a few UX improvements to make it more utilitarian. When I hover over text and click the link button, it just pops in a sample link code, instead of converting my text selection into a link. Little things that make the experience less clunky.