Not Fediverser per se but the underlying concepts. In detail:
Content is King
Here, PieFed is no better nor worse than Lemmy. It uses ActivityPub to connect with Lemmy, as well as having its own communities, like Mbin (except unlike the latter it doesn’t have its own separate voting system, nor does it federate with Mastodon).
One thing PieFed does have though is the ability for someone to block all users from a particular instance of their choice, without requiring admin approval. This helps SO MUCH for certain instances that nobody wants to defederate from… yet I don’t want to read content from either.
Painless onboarding is second. Fediverser is meant to help with that, but no other admin has shown interest in adopting it.
There is a wizard where you choose what content you want to see - News, Politics, Arts & Craft, Technology, Movies & TV, Science, etc. - which then signs you up to communities in those Topic areas. You can later unsubscribe or subscribe to any individual communities that you wish, but the wizard helps the onboarding process so that you don’t have to simply stare at All bc your Subscribed feed is initially empty, as Lemmy does, bc on PieFed it would not be empty. It thus makes it much easier to find less prominent content, such as poetry, that would otherwise get swamped out by all the memes and politics and such.
A clear way to find-what-goes-where is third.
There are Categories of Communities that combine posts from all of the topic areas, whether you joined those communities or not. So if you don’t want any politics filling your feed, yet you occasionally do want to look up something related to politics, it is just one click away. So not quite mapping specifically to Reddit subs, but yes mapping to content areas - which imho is so much better, bc that would also help someone migrating not just from Reddit but from X, or Bluesky, or Mastodon, or Lemmy, etc. You don’t need an account to see this feature btw - just visit https://piefed.social/ and look at the top.
Or here is an example post showing the Categories above the post, hashtags below it, YouTube embedding of the link, a link to watch that rather on Piped, and if you scroll down note how the sidebar text appears below every single post (some apps make that exceedingly difficult to find on Lemmy, but it’s very often helpful to see not just when on the community page, and rather when in an individual post, e.g. to read the rules).
Does it provide a separation between topic instances and user instances?
No, there are extremely few instances so far and the whole project is still in late alpha as it adds features to catch up to Lemmy, although as detailed above it already has many features that Lemmy lacks. And I didn’t even begin to get into some of the best thoughts for how to democratize moderation practices to rely less on authoritarian control of “remove” vs. “allow” content, by expanding upon those binary choices to include user options to control their own experience - e.g. automatically collapse any comment with >20 downvotes (though it can easily be uncollapsed with one click), and labels next to usernames (e.g. “account <2 weeks old”, “may be an unregistered bot account that posts but never comments”, “controversial user receiving >50x downvotes than upvotes”, etc. - except these are icons not words as I relate here, plus you can add your own icons whenever and to whoever you wish, that only you will see, on top of these conditional-based ones), and even more than this besides.
When it catches up to feature parity with Lemmy, damn it’s going to be so exciting! Right now it’s more of a future thought, except I (who know how to fall back to Lemmy when the occasion demands, e.g. when searching for a post) already use it as my primary daily driver - not that I would recommend that mind you, just saying that it’s possible, if that gives you any indication as to how close it is to being ready for the masses. It’s very close, I do believe!:-)
It’s been too long, but there might be a way to click all at once or some such. But those are details, compared to Lemmy that has All or None (and empty Subscribed), with nothing whatsoever in-between. It’s a step in the right direction I am saying.
Nothing will ever entirely “solve” anything at all - people even on Reddit complain about “lack of content”. There’s tons of content here though, it just gets really difficult to find it. However, check out this link for Arts & Crafts. There are lots and lots of posts there - PieFed shows like 5x more in a listing than Lemmy - virtually none of which would make their way to All bc of being swamped out, and yet if that is the content that people are TRULY looking for… this brings them straight to it, with one click! Why isn’t that a “solve”, at least for the issue of content discovery?
Then they can subscribe to the communities they want to see in their Subscribed feed, which is less relevant due to being able to use those Categories. Also you can trigger a Notification for anything at all on PieFed - a user account, a community, a post, and I especially love seeing that you can turn OFF notifications for a particular comment, if abusive trolls decide to spam you for WEEKS and WEEKS afterwards, which is a real story that has happened to me at least twice on Lemmy, once on hexbear.net and another on lemmygrad.ml - in either case, my consent ceased long before they eventually got tired of harassing me (in fairness, that is supposedly what communities such as [email protected] are for, so it’s not that I want the community to cease to exist so much as to not have its content promoted as if it were adopting the same standards of behavior as every other space that I was used to across the Fediverse, without at least a warning of some kind delivered, which is yet another beneficial capability that PieFed offers).
So in addition to Categories and Subscriptions, I also have Notifications sent to me for lesser-trafficked but highly desirable content for me to see like [email protected]. And sometime this year there will be yet another method of handling all of this, in user-defined topic areas like a Favorites or other category of content that the user asks to be separated from all the rest.
And respectfully I disagree, bc depending on implementation, Categories of Communities has the advantage that it could make discovery of new communities obsolete - e.g. if there’s a [email protected] and a [email protected], it could put both of those into the same Category, and isn’t that what you are essentially asking: that wherever the content ends up moving, that the software go and find it and bring it to you, wherever you happen to be at?
Granted, the solution that PieFed offers needs to be improved upon:-), but at least it exists now.