Yeah this part didn't make any sense to me - is he claiming that later interviewers will be heavily biased by talking to previous interviewers? If so, I think that's probably not as strong an effect as he's claiming, and its also easily correctable by just having interviewers not talk to each other.

I do agree about the "you only need 15 minutes" part, but the solution there would seem to be replacing four hour long interviews with four 15 minute interviews, rather than with 1 hour long interview.