tl;dr: Ragnaros Heroic 25 is too hard.
I've decursived on Lucifron. Out-of-combat ressed on Baron Geddon. Fought the first, unkillable incarnation of Ragnaros at 60. Fought Vaelastrasz for an hour. Fought untauntable drakes. Farmed Mauradon for Huhuran. Fought Claw Tentacles in C'thun's stomach. Been killed outside Naxxramas after an hour and a half of Loatheb prep. Leveled a Warrior for The Four Horsemen. Farmed Black Temple for nearly 10 months. Killed Kil'Jaeden before M'uru got nerfed. Breathed a sigh of relief when Yogg0 got nerfed.
Now I'm on Ragnaros Heroic 25 and for the first time in my substantial history raiding in World of Warcraft I am on the verge of giving up.
This isn't an encounter that you bang your head against until "that guy" doesn't get Defile. This is an encounter that doesn't permit you to have "that guy" in your raid at all. Of course, he also punishes you horrendously for bringing anything but the perfect set up. I'm not going to argue that the encounter is impossible without a perfect set up - it isn't. I will say: Paragon's line-up. Did you see how their live raid went?
Anyway back to "that guy". Every guild not currently marked 7/7 on the wowprogress.com frontpage has them. As you flip through the pages the guilds you're seeing get fewer and worse applications. They make do. They have "that guy"s. And Ragnaros, unlike any of the encounters I mentioned above including the often voted "HARDEST BOSS EVAARRR" M'uru (he wasn't) doesn't allow them to. "That guy", along with every other member of your raid will be required to flawlessly execute with perfect consistency several tasks throughout the encounter. The coordination Ragnaros demands from 25 of your raiders is what you'd expect from a highly trained team of Navy Seals. The slightest chink in your raid's armor, the tiniest error in judgement, anything but the very best performance from one of your players and you crumble like you just found all those people in your ventrilo channel in trade chat.
We along with many other guilds might kill him. In several months when we're decked in 391. But it will have stopped being fun long before that. Soon my raiders will start to despise each other for not being the machines this encounter requires them to be. They'll quit and I'll have to fill the gaps they leave with even more infuriatingly incapable raiders until either Ragnaros through an act of god falls over, or my guild does.
I urge Blizzard to step away from this 6 joke bosses, 1 horrifying monstrosity of a guild ender model. It's killing my inner raider's soul.