Centralization is natural, even in the fediverse. A successful lemmy is going to look like tens of large instances, a few hundred medium instances, and a ton of tiny and irrelevant instances. Even if federation and discovery get more transparent it's still likely going to be mostly centralized.
Owners of larger instances should freeze people making new accounts and point them to a site that can list other instances maybe for periods of time. There should be some sort of pledge amongst instance owners to help the fediverse where they aren't hard rules but things to try and do
A block like this would have probably kept me from making an account here, and I'm an IT tech.
(I tried to create my user on Fedd.it, but it simply wouldn't let me. I tried 10x. So I'm on lemmy.world because here, it worked.)
We don't need anything that makes entering the Fediverse harder.
There's only one person to blame for the sudden explosion of users of a new and undeveloped system. I see this all as a good thing to happen in the beginning, as it will help improve and solidify solutions now, rather than years later when things are more established. There will be shuffling and mirroring of communities, and tools made to help in that cause, and all of that will make the overall fediverse better.