Releasing the source code to the clients would also address many of our concerns.

How would that make a difference for plugin security? Almost all plugins are already open source.

If you mean for the security of the app without plugins you can currently inspect the app's code in app.js and review third-party audits:

https://obsidian.md/security

LMAO. That won't happen in a million years. They are bending over backwards not to give proper file access on iOS so they can sell subscriptions. Do you think they would do such a crazy thing? I bet you my life savings it won't happen.