Based on two unscientific polls I conducted here, people's biggest fears about the future of the Fediverse are: 1) volunteer moderator burnout; 2) too much defederation causes fragmentation; 3) people are driven away by racism; and 4) Mastodon.social gets too big.
Here are the polls:
https://wandering.shop/@annaleen/110318754714238485
https://wandering.shop/@annaleen/110318806416458197