What about a new mixed-feed which merges the Subscribed, Local and All feed based on probabilities customable by the user e.g. 10/40/50 or 0/20/80?
This would push users toward local posts (especially on smaller instances) while still supporting a better distribution of user engagement over the threadiverse. And if you don’t trust that it was implemented correctly – you can simply check it by counting the amounts of posts against your chosen probabilities.
No it doesn't. It addresses a different problem, namely: posts from small instances should be somehow boosted in my feed.
The problem I try to address is regarding posts from my local instance vs. posts from all federated instances. I would like to have a sorting that gives up a good mix here and that would also be in line with admin's motivations to keep their instances alive. As described here: https://lemmy.world/post/5110168 their chose to promote the All/Explore or the Local feed can be modeled with problem from game theory and can result in admins to choosing to promote only the local feed if they find that the All-feed gives their posts a disadvantage and over long, drains away their user engagement. Scaled sort will not be able to fix that.
(Actually should have written that in the description)