Whatever happens, I would encourage people to be forgiving. As Brian Krogsgard mentioned in his short take on poststat.us, it's important that any system is careful to not push out new speakers who could improve but might be too discouraged by bad reviews after their first talk.

I have seen a way-too-self-promotional presentation from a relatively well-known WordPresser which left a bad taste in my mouth, so I see the need for something, but we should be careful. Having organizers review notes and slidedecks preemptively does feel like the best solution to me.