Everything has had its damage and health cut, and anything that requires coordination has been severely nerfed or taken out.
e.g. second boss switches phases after a certain amount of time regardless of whether you hit him with the orb. third boss spawns only two globules. the aspects on fifth boss will never eat a full hour of twilight. etc.
The orb also automatically splits between players in a much wider radius. You don't need to move as a group to intercept orbs. As long as one person hits the orb, it will bounce and damage will split between the raid instead of 1-shotting the player. In the normal mode, almost the entire raid needs to move together to hit the ball (in a ranged and a melee group). In LFR mode, only 2/25 people need to worry about it.
That is not remotely difficult compared to any other class in the game bar Arcane Mage. I don't think you use recuperation in assassination; that's sub that uses recup for energy. Every class has CDs, and the rogue ones are of pretty long CDs anyways.
It just boils down to putting SnD up, keeping rupture up and spamming Envenom, and using Backstab for CP <35%. It's not like you're anything close to GCD capped.
I think you over-estimate how complicated other DPS classes are. The basics of an assassination rotation is what you've listed. Keep SnD up, Rupture immediately when it falls off unless you have enough energy to mutilate and then immediately rupture, Envemon at 4+ combo points unless you're about to lose SnD in which case envenom early to renew. The difference between a good assassination rogue and a bad assassination rogue will be:
1) coordinating cooldowns for maximum possible dps.
You have 4 dps cooldowns in T12 gear (cold blood, vendetta, vanish(into garrote), ToT) before you include trinkets, consumables, or cooldowns from other classes like heroism. These aren't all on the same cooldown duration. You need to know what cooldowns you can afford to use early in the fight that will be up again before a burn phase or a cooldown like heroism/bloodlust is used, and what cooldowns you need to save. Basically, maximizing cooldown usage without missing windows where you could have stacked cooldowns for better damage.
2) maximizing attacks while the envenom buff is up
Pretty simply concept. You want to save as much energy as possible before you 4+ cp envenom, but not so much that you energy cap from relentless strikes. This will allow you to get extra mutilates in while envenom is up, which will lead to more poison procs.
That said, it's not that hard to maximize assassination dps on a target dummy. I don't think any class is, even something notoriously demanding like subtlety or feral cat dps. It gets hard to maximize everything when you're in an actual fight dealing with other mechanics that will impact the best time for cooldown usage, and potentially distract you. Assassination is less about staying on top of the GCD, and more about planning ahead for energy and cooldown usage.
I actually think rogues are one of the most engaging classes to play, because you also get a lot of defensive cooldowns to use and other things to do when you aren't GCD-locked.
