This is a confirmed hotfix. It pretty much removes the option to use a ranged tank, since aggro generation shouldn't be any problem now for the regular tanking classes, which was the only real benifit of having a ranged tanking class. Well, that, and maybe the ability to gather orbs more efficiently although in my opinion that's more dependant on the player than the class.
Edit: You didn't really need a ranged tanking class in the first place.
I'm really not sure where you reach the conclusion that this removes the option of using a ranged tank. If anything, this is an improvement for ranged tanks. Previously, ranged tanks had to worry about melee hits and survival issues if Keleseth was the second empowered mob. Both of these issues have been removed.
Now, don't get me wrong, I'm a firm believer that no one should use a ranged tank on this fight. It's still a much higher risk than using a proper tank
I also don't see how you figure that this helps with aggro generation in any way for proper tanks. I was able to generate more than enough threat to have Keleseth stick to me while I spent the entire empowered phase and most of the other phases grabbing new nuclei. Threat was never a concern for proper tanks, though I could certainly see it being a concern for ranged tanks.