I'm not going to complain about the increasing nerf. It certainly makes heroic modes much more attainable. This past raid week we put some learning in on Yor'sahj and got him to 40%. He's typically the second heroic kill for guilds so we should have him soon. (For whatever reason we found heroic Ultraxion easier.)
Let me tell you, the 10% debuff does have some weird effects on normal modes. We have easily nine-manned bosses. Last night, our raid leader jumped "accidentally" off the gunship. I suspect he just wanted to /afk on a boss we don't use call-outs for.
On normal Deathwing, we were taking down limbs before they even started casting Cataclysm. Then we wiped because we did too much damage. We brought limbs down to below 70% just as a tentacle popped; This meant we were spread out for the tentacle but we had blistering bloods on the limb just ripping us to shreds. So we had to dial our dps back a ton. We are working on the Chromatic Champion achievement to learn the fight in different ways.
It is kinda nice to think that all the heroic modes are within reach. I can't recall thinking that before.