I think it's perfectly reasonable to hire people based on resume, references, and conversation. If they can't handle the job once hired then they should be let go.
I do not think that the idea that all candidates are complete idiots unless they can be "proven" to be good engineers (by faked tests that rarely cover the actual job requirements but do have a way of discriminating against those who don't enjoy brainteasers, didn't go to college, or are older) is good or healthy.
This does assume that the interviewer is an expert in the area and can take that friendly conversation to the necessary depths.
I have, however, on two occasions probably personally convinced someone they had dodged a bullet by passing on me when I bombed that sort of quizzy interview—they were, I am entirely confident given the job descriptions, my work history, and actual feedback I've received from managers and peers, quite wrong, but I bet they were very sure I was useless and nowhere near being fit for the job.
[EDIT] I guess I should add that I have a history of not realizing that something I'm good at is not actually easy or obvious to others, so possibly I'm just unusually awesome at assessing developer suitability through conversation—I really doubt it, but maybe that's what's going on. I've also not found a way to make this fit with any sort of "we ask everyone the same set of questions because we want spreadsheets at the end" process, as you've got to tailor the interview to both the position and to the candidate, as presented on their résumé and related material. So if you want spreadsheets and quantifiable-everything then I'm not sure how you match that up with my preferred style.