how is this realm different from others?

Besides the fact that this realm is hardcore, and 1x obviously.
I have a question that has been troubling me, for a LONG time now I've been looking for a realm which provides what the retail had.
But in most of them due to the 3.3.5a talents and class balancing most players do ****loads of damage at Naxxramas content.
People in private servers I've been to could get to about 6-7k dps single target.

Is that the case here? and if no what steps did warmane take to fix that issue? Did they nerf most classes or do anything in particular?
Leveling in 1x is frustrating, I just would like to know what I'm getting myself into before going balls deep into this leveling thingy.

Thank you very much.

They didn't nerf classes, but instead they buffed the content damage and HP. It still didn't stop the people of completing the raids while you execute the tactics properly.
So yeah, the special thing about this realm is that the new content comes with buffed boss and mobs damage and HP, which based off the community feedback gets lowered or increased.

Also no rdf.