An #ActivityPub protocol extension where you can host your own identity server or use a public one and login to any ActivityPub service through that (thereby using any interface with the same Fedi account) would be kinda nice I guess.
Being thrown back onto a different platform (and the corresponding interface) just to comment is really bad in terms of UX. 😕 It kinda works for (Micro)blogs, Image Blogs and Video platforms. Forums probably too... but Link Aggregators like Kbin or Lemmy? Meh.