The proposal would allow one community to follow another

Who determines when a community should follow another? The admin? The user?

If its not an issue for you, then you lose nothing if this is implemented,

My point is that it a lot easier to implement something that solves the problem that you are describing than asking for a whole change in the implementation of the server.

The nodes are the servers not the clients. (...) The reason most of the fediverse uses the MastoAPI (...) is because the C2S expects a more client focused ecosystem but all the developers find it easier to handle logic on the server.

It's a trade-off between speed to deliver the base case vs the lack of flexibility to deliver a more flexible version of it. And the more that we push to the server, the slower it will be to be able to extend it. Case in point: People have been complaining about the lack of algoritmic timelines on Mastodon. The Mastodon developers will find all sorts of excuses to not have to implement it... "Algorithms are bad for people", "People are just too used with how things in Big Tech", "we rather working on moderation and safety"... etc. All of those are bad rationalizations for them to avoid doing work they don't want to do. Which is fine, the devs are not forced to develop anything. The interesting things is that this problem was solved a lot faster by flipping it around and pushing to the client. And it works so well that that people now can even choose what type of algorithm they want to run.

Your argument is the exact opposite of what every fediverse developer says.

Not every developer.