Yeah, I'm a Prime member. It was just too much trouble to deal with it though, so I chose to vote with my wallet. I agree that it was a pretty lame response on Amazon's part. I mean come on, I thought they'd at least price match Best Buy. No dice.
I would assume that one needs to chat with a CSR to get the extra discount? Seems like a big YMMV.
EDIT: Yep, just chatted with an Amazon CSR and came up empty-handed. Told her that Best Buy, Target, etc. will have this title available on release day, the 5th, and asked why Amazon was delaying...