1. Noone understand what "federation" is so they all flock to the big servers hence making the majority of the system totally non-federated in nature
2. Findability (of users, topics, servers) is terrible which pushes people to 1)
3. What you said. Until there's such a thing as federated identity, we're all still tied to one server, thus one server owner can ban / switch off / over-moderate and we're all back to square one
Some of this can be solved with ux and education but I worry that some of it is basically baked in to federation.
Edit: yeh I mean in theory you can move servers but it's apparently not easy...!