On the eve of the 10% Dragon Soul raiding buff tomorrow night, it gives me great satisfaction that our 10man raid group managed to sever Deathwing's spine today with only the 5% buff up.
We had been working on Ultraxion prior to the 5% buff and just missed killing him with our own power - I'm pretty sure 1 week's worth of gear upgrades for people would have done it - so the kill on Spine was some great timing.
Not to mention, we managed both Blackhorn (a fight we were still a little shaky on) and Spine without Bloodlust, since we had no shaman/mage and our raid leader was confident that we could do it without, even though I've usually volunteered to switch to BM for Ancient Hysteria in the past.
Hunter note about Spine: It seems to take at least 3-4 Arcane shots (less if you get an auto/Chimaera/insta-Aimed in there) to break Fiery Grip, so doing less DPS but keeping a full bar of Focus ready is important, especially when you have to break someone out close to Rolling or Tendon phase.
It'd be interesting to try the fight as BM - with the lower personal DPS it might be more difficult to break people out quickly, even though you'd have better burst DPS available for killing Tendons.