I don't care too much about the Fediverse in itself; I was looking for an old.reddit.com-style place to share all sorts of hobbyist and technical content and have meaningful discussions on it. The interface kbin is offering suits me aesthetically better than the alternatives, so I am sticking with this site now. I like the clean but not too sparse feel, the simple threading, and the ease of browsing magazines. I would like to see comment thread collapsibility and easier navigation within a thread's comments (remove or improve pagination, for instance).
There are many limitations, but these can also be opportunities: precisely because this site is in its infancy, it has the potential to incorporate ideas from the community much faster and with more forethought than a mature, established product.
For my part, I would like to lobby slightly for native LaTeX rendering throughout kbin.social, similar to what mathstodon.xyz has. It is a somewhat niche functionality, but it would put math, physics and computer science-related magazines far ahead of corresponding subreddits in infrastructure.