However, he paled in comparison to M'uru. The portal voidlords, the small adds that spawned in the middle, the adds from the outside, and the 2.9M health on the boss during Phase 1. It was just a crazy fight and anyone saying those who didn't kill it pre-nerf didn't have skill has absolutely no idea what they're talking about. I didn't kill it pre-nerf so this isn't about some sort of prestige. I just know that it was one of the most tightly tuned fights out there with absolutely zero room for error. Phase 2 wasn't as harsh but you still had to pump out some major damage and have the raid ready to move to avoid the black ball of 'look mum no hands!'.
Felmyst was sorta the retard check of the entire instance. You still had to push the DPS, but avoiding the clouds was the only major challenge with that fight. Basically, if you could kill Brutallus with ease, you could do Felmyst without a problem. Twins were somewhere in the middle of difficulty. They required more co-ordination than the previous bosses, but it was very subject to RNG at times. Conflag wipes were common, but it was perfectly manageable as long as you had good raid awareness.
So, SWP required a level of skill that you can't simply dismiss.