Yes although me being primarily a lurker I need even less. More than post or comment, if I have an account it would be to block some things and prfioritize other things more closely. What you describe would make sense for more extended functionality, but there is silent majority of lazy lurkers like myself that could be served very easily.
So my model would be one where you pick a site as your front end, most of which would have default curation and subscription to various subs, providing an experience like /all by default.
Though it would look like /all what it would really be is more like an RSS reader aggregating multiple sources according to your preferences.
A Reddit alternative would naturally form in this ecosystem, with smaller alternative front ends abounding, and take dominance just as Reddit did, but unlike Reddit it would not be able to screw over sub mods etc.
Subs would be truly independent of the front end site, even if they are themselves also front end providers.
It's Distributed Reddit in a sense.... Though in my view it'd be best to make it content agnostic, so it can be adapted to other uses, specifically for a YouTube clone and such.
Really, there's a model where for most it's essentially a Facebook alternative that integrates into thousands of third party forums seemlessly...
I would use that. Please go for it! It's so obvious to me. There's a giant discoverability gap in the whole fediverse thing that can be easily addressed. This is by design in mastodon, but I don't think these reddit alternatives are so against virality. The only risk is that the whole thing fizzles out so hard that even an aggregated view of the entire ecosystem doesn't produce enough content to keep people engaged.
If you do it, please keep in mind merging submissions and their comments, 6 separate entries for the same thing each with a couple of comments is a much worse experience than a single entry with a dozen comments. You can start by simply using the URL as a grouping key and try more sophisticated things later.
