I think one of the important takeaways from the talk is that even if people say they want brutal feedback they probably don't. More importantly, feedback can be totally honest without compromising it's optimism.

> I would much rather get a code review of "Missing tests for negative numbers, empty string, null" than a longwinded and "nice" version

I agree that niceness isn't always necessary. Fortunately, that's not what the talk is about. For me, the examples you gave actually fulfills all the criteria for optimistic criticism:

- It's impersonal: the focus is on what the code is missing, not your ability as a coder.

- It's specific: there are hyper-specific criticism.

- It's temporary: the tests are merely "missing" and that's a condition that can be quickly changed.