The problem, as I see it, is one of resources. Even instance owners who are programmers (<raises hand>) can't afford to take the time necessary to get enough into Mastodon's code to understand how it works -- and that's just the first step in rewriting or modifying it -- no matter how much we'd like to.
So, somehow we have to secure sufficient funding for at least one of us to be able to focus on this while also paying the bills.
(I could elaborate further.)