Mining centralization is at spooky levels, but that's a market condition that is transient and already healing by the day.

Distribution is a concern, but not critical. That's a reflection of the real world economy, so again market driven, not technical.

Culture/incentives are probably the biggest risk, there's very few principled people that have the ability to do principled things. Fortunately, bitcoin's technical design is literally built to mitigate that cultural/incentive risk. Every time a script kiddie or NGO wants to change Bitcoin I appreciate it for what it is even more.