nostr:npub1lqxauw3yjjf8y5sma55e34ux4td3u7mppkl20qz4na23gh8vj8jsmarj5c has a good write up comparing the two protocols. 

ATprotocol can be open but it’ll never be permissionless. There is an approval process for each PDS connection to each relay and every kind of content will need its own appview server. The hard enforcement of schema validation means new data types don’t work on the network unless they go through a kind of standards process and then explicit support is added to the client, PDS, and appview amongst other places. 

Their name system was supposed to be a temporary bridge to an open system, it’s called did placeholder, but they know decided they’re keeping it because they do want a control over usernames. 

The last bit is that PDS’s control your keys and there is no way to request or move your keys. You can only migrate with a manual process that the PDS provider does on your behalf. If your PDS provider, which is 99.99% of the time Bluesky inc, doesn’t let you go then they own your account and all of your data. 

Lastly Bluesky isn’t going to do encryption. The dm system is an unencrypted centralized system where Bluesky has everyone’s private messages. They have no plans on changing that or adding encrypted groups. 

Bluesky has made a bunch of decisions which have helped it grow and in building these systems there are always tradeoffs.