I want to narrow down the topics I'm looking for without needing to search and subscribe to each instance. So instead of going from All to Subscribed, which have a lot of non-startrek content, I want to view all of the startrek subs across all federated instances even if I haven't subscribed.
This sounds like what the OP is asking about, although I would actually love to just pick some strings of text and save it as a subgroup. If I don't like one or two of them I can remove them from the list, but while browsing my startrek subgroup I get to see content from newly created startrek magazines without needing to regularly search and add them manually.
That would result in seeing content across instances at the same type for the same topic without needing to keep up with new instances. And to be honest, I don't care about instance specific rules. I just want to browse and interact in a respectful way and if some instance has silly rules they can let me know I broke a silly rule and I'll bow out of theirs.