The challenge isn't figuring out how you or I personally would deliver feedback, given time to plan it out and a good set of feedback to deliver. The challenge is establishing a process that ensures everyone at the company will always do it, even when the real reason is something like "meh I'm not sure the candidate quite clears our bar".
> even when the real reason is something like "meh I'm not sure the candidate quite clears our bar".
That's the problem, though - you're trying to make a hiring decision on hopelessly incomplete information, and so it will come down in large part to gut feeling. And the moment you admit to using some non-quantifiable feeling as a basis for not hiring someone, you open yourself up to claims of some form of discrimination.