I don't know about crucial, and I'm not sure if it exists already and I just can't find it, but I'd love to be able to preview a comment or post before submitting it.
Something similar to the multireddit function that reddit has where you can use a + sign in the URL to consolidate multiple subreddits in one page? I don't know how easy this would be but if you could do that across multiple instances you could have askkbin+asklemmy@lemmy.ml+asklemmy@lemmy.world (etc) and view all the different questions at once.