What you fail to consider is the purpose of this nerf. T3.5 was not nerfed to cater to casual raid groups or OPRs. It was nerfed to be accessible for unorganised PUGs that come together using FC's future raid finder. I.e., a bunch of people
* who have never played together in this setup,
* some of whom don't have any experience with the encounters,
* some of whom don't even use voice communication, and
* many of whom only have very limited resistance to wipes. (Because instead of wiping, they will try another raid finder PUG and hope for a larger number of vets to carry them.)
I am pretty sure that this is the reason why they butchered mechanics, instead of simply making mistakes less punishing. Not saying this is good or bad, or whether it could have been done better (probably yes). But I think it explains a lot.