Like I said, I can’t force you to see it.
In a scenario where Lemm.ee would have become a content instance, but kept their federation policy, they would still have received all the reports about posts on the communities they hosted, wherever the reported user comes from.
Being a dedicated content instance provider would also inherently imply dedicating that instance to a certain, more controlled type of content. An authentication instance might want to cater to a geography, which will probably decide to interact with the rest of the world and to provide adequate verification and certification mechanisms. A content instance might want to cater to a geography or a subject, resulting in specialized participation, with certification and verification based on the content, not the user.
You keep seeing monolithic instances that congregate the most communities as a plus. That’s a negative in my perspective on the fediverse. It shouldn’t be competing reddit clones with the one having the most communities winning out.
Like I said, I can’t force you to see it. The fact that you think it would mean re-engineering the whole platform means you aren’t getting it. It’s almost literally the suggestion of least effort, it’s largely an organizational change that encourages instances not to cope with more responsibility than they can deal with by encouraging decoupling the current structure into two more specialized ones.
If you want re-engineering the whole platform, then I would suggest having all instances be authentication instances and rather than “host” communities to allow users to broadcast to community labels. Have any number of moderation groups be able to be created in an organized on that label or a personalized way by allowing users to select their own curators, perhaps even extrapolating it from the downvotes of trusted users and prioritizing the ranking of those they value. Work on providing a ground.news of discussions instead of biased takes and prunings from those in charge. Allow fast tracking of moderation across these adhoc groups for specially toxic content. That would solve the problem of nobody really going from a 10000 user community that has 100 daily posts to a 10 user community with 2-3 posts a week, because they would all operate within the same community but every user would be able to customize their perspective. The risk then is to balance the bubble they’ve created with transparency of all the other bubbles people are creating to interact with the community. Each particular instance would be able to be as biased as it wants to particular users or groups of users, but their content would truly be broadcast and federated.