I don't mind a community having low amount of content. It's easy to just join multiple and hop around. I don't mind a UI not entirely matching my preference, that stuff is "matter of time".
But Mastodon made it VERY hard to find the little content their communities did have. They have an anti-Trending philosophy, and that drove me, and most people I know, away. When I joined, they didn't even have proper tag searching, and to this day, the activity in a tag is still reported wrongly. When asked, I got aggressively told off that Text Search is evil and I'm evil for asking and no, I didn't even talk about twitter but I'm evil for even daring to make requests even lightly resembling a Twitter user's UX preferences (Aka: Discoverability and UX). I just wanted to hear a "oh that's broken and being worked on" but no, it was always a "no, we don't like that" instead.
No such thing here. I wanted to find the gaming subs, I found the gaming subs. I wanted to find a desolate abandoned community for Dota 2, bam, I found the desolate abandoned community for dota 2. Within 2 minutes I was on grounds with /c/PatientGamers.
It got slightly better. But won't ever fully fix itself. To me, and to a couple colleagues, Mastodon was a bad website, with bad gatekeepers and a bad advert for the Fediverse. I don't care about it and I hope Rhynodon some day comes, implements text search and steals all their users.
Big upvote. I figured out how to follow other communities from clicking the community tab at the top and looking at the URL. But it shouldn't be this hard. It should be way more seamless.
There's two things I wish this had:
(This is your suggestion) Lemmy websites and apps should automatically attempt to show external communities within their own website if possible, so that sharing a community from this one will still allow you to join up without further navigating
When seeing a "subscribe" button on another website, instead of it assuming you want to subscribe from the site itself and telling you to log in, it should first check if you're not logged in, and if you're not, also give you the option to subscribe to it from another instance if it finds any browser cookies for other Lemmy communities.
With that said, both of these might be against the goals or require the cooperation of an instance, so if we ultimately end up not getting it, well, it's fine-ish.