Centralized staking: Yes, it’s a concern, but so is centralized mining. We’ve seen real-world 51% attacks on PoW chains due to mining centralization.
Weak subjectivity: True, it’s a real factor, but not a showstopper. Clients just need to use a recent finalized checkpoint.
Slashing risk: It exists in theory, but we haven’t seen it hit honest validators in practice, even on smaller PoS chains.