This is probably the biggest issue I have with Lemmy right now. To make matters worse, it's really easy to miss how the system works. A lot of new users on smaller instances probably think this place is a ghost town because they don't see many communities in the directory. It's not ideal to have to use an external tool to find communities, then extra problematic that the actual process is so awkward: manually pasting the address from the external site in the search bar, then you get a "community not found" warning but ignore that, then the community will appear but it'll grab the old posts and not the comments. Weird.

I can accept that it would be too much if every single instance defaulted to a full local sync of every other community on every other instance, but they should at least show up in a list when searched for, IMO.

It may make things simpler for the user, but at the cost of storage and performance of every instance in the index, which won't scale well as more instances are added over time. I personally think it's better the way it is. As long as you are educated enough to know how to federate with other instances you choose to federate with, you can keep your own instance minimally connected to only the instances and communities you actually care about.

Maybe a good compromise would be for such an idea as a globally replicated index, to be optional, so individual instances could keep it disabled if they wanted to. If you choose to enable it as an instance owner, the pain points for your end users go away, at the cost of performance and other potentially negative side-effects. If you choose to keep it disabled, you can still federate with any instances you want, but you won't participate in the index. Or maybe your instance would be listed and replicated to other instances' indexes, but your own instance won't receive updates as the global index continues to grow. Since it would just be for convenient discoverability, there's not really any problem with that. No functionality would be lost for your or any other instance.

I mean, you dont have to do it personally. Just someone from your server has to tell the local server "hey, im interested. Please give this server a feed" and then everyone on that server now gets a feed. You can also use the community search and just select all and then it will search out and then you can subscribe from that page. It's basically a master list of communities. For instance https://lemmy.world/search/q/pokemon/type/Communities/sort/TopAll/listing_type/All/community_id/0/creator_id/0/page/1 then everyone on lemmy.world now has to deal with an influx of pokemons...

I might be misunderstanding but it basically works the way you want it to work but in a different way than you want it to work.

Am I just misunderstanding this, or would the end-user experience be more fluid and functional if the federation mechanics were mostly ‘under the hood’.

I know what you mean, but I'm not sure it's a good idea. Look at the recent beehaw-defederation drama. This would have been totally intransparent if the whole federation thing would be something that's only running behind the curtains.