It's a double edged sword. Yes, mastodon.social is large and unweildy, but as the default it kept me from ignorantly joining a toxic instance like beigeparty. I'm for change, but it's yet to be seen how this plays out in practice.
A better solution might be something like an official introductory instance where you get 6 months to get your footing and then it prompts you to migrate and gives you a selection of vetted servers. Like pushing a baby bird out of the nest.