"I just reviewed all open and closed bugs in TextSecure's Issues page and didn't see a single crypto protocol bug. Admittedly, I looked quickly and casually. Could you point us to one?"
You could not have reviewed all open and closed bugs in 8 minutes ;)
Issue 1073:
https://github.com/WhisperSystems/TextSecure/issues/1073
Another one: Just sent an encrypted photo to someone? The photo is stored unencrypted on your phone.
Edit: group messages were also sent unencrypted, but this was fixed. https://github.com/WhisperSystems/TextSecure/issues/32
Edit2: ok, I see your point. Maybe they do crypto well as you say, but they don't seem to do software engineering well, or UI design for secure text messaging well. Sending messages unencrypted, and leaving messages unencrypted on the phone is a big fail in overall security of the app. It's meant to encrypt things, and it doesn't. That it doesn't put in tests for these things, and that it did not publish the independent security audit should cause everyone to reconsider using the TextSecure app for its stated purpose.