i feel like blocking of instances leads to worse echo chambers than subreddits themselves. We gonna have bubbles of federation networks that don't federate with each other. E.g. lefties, righties, "dark web" illegal shit, kinky shit, and instances that federate with all of them will be blocked by other instances because "use my blacklist or get defederated". This is gonna lead to hell for users having to create fifty accounts for each bubble. Aint nobody got time for that.
i wish it remained a user's option to block/unblock content they don't/do want to see. Each instance could provide their "recommended" default list of enabled instances, and user can go and enable others, like how NSFW toggle works. Maybe group instances into categories with tags or something, like "porn", "memes", "tankies", "nazis", "warez", etc
Either way you call it, it's someone else deciding for me