There are a number of glaring problems with Affliction as it currently stands.
1.) The rotation is overcomplicated. This is the biggie, and it's a large contributor to the other difficulties with the current Affliction tree. The Affliction rotation is not only a tremendously dramatic change from the Shadow Bolt spam of yore-- warlocks went from being arguably one of the easiest classes to succeed at in end-game raiding to far and away the most difficult class to play effectively when the new Affliction emerged as the dominant spec. The Affliction rotation is an *eight button rotation*. No other dps class in the game uses even half this many abilities to dps effectively! And the more complicated the rotation, the greater the room for error, yielding dps loss on account of lag, PEBKACing, and so forth. There's a reason blues have cursorily acknowledged that the rotation is a bit much. The crack about Affliction being the black diamond slope of warlocking is not an exaggeration. The rotation has to be simplified.
2.) "Rotation" is a misnomer-- there IS no rotation. I call it a rotation, but the fact is it isn't one. Every other dps class in the game has a pattern in their abilities emerge. If you monitor a well-played affliction "rotation", giving proper priority to DoT refreshes and using Haunt on every cooldown, for an infinite period of time, there is no actual pattern that will emerge. There are no other dps classes that suffer from this difficulty. It poses a tremendous challenge for any fights that require you to do something other than stare at DoT timers the entire time. Speaking of which...
3.) The spec is over-dependent on external addons. Affliction is frankly unplayable without a DoT timer of one form or another, whether it's DoTimer, Quartz, Necrosis, or something else. It's straight up not possible to play with any sort of finesse without using external addons. Blizzard has stated on a number of occasions that such a situation is undesirable, and in situations in the past where it's become a problem, Blizzard has remedied the issue by either implementing a function within the game to serve a given function (see the upcoming internal threat meter for example) or has modified a mechanic to make it such that it's no longer necessary (see the removal of the necessity of Intervene macros for example).
4.) The debuff limit is an enormous obstacle. A single warlock adds the following debuffs: a curse, Shadow Mastery, Haunt, Corruption, Unstable Affliction, Immolate, and Siphon Life. And what does a second warlock add? Another seven debuffs, because none of them stack. That's a full third of your debuffs in a 25 man raid being consumed by two members of your raid group. What about that is fair or balanced? There are two possible solutions to this problem: increase the debuff limit, or simplify the number of spells in the Affliction "rotation." Blues have already stated they are disinclined to change the debuff limit. Guess that leaves one solution.
5.) The spec is not supported by WotLK gear itemization. Existing beta itemization goes one of three ways: You get spell damage and hit, spell damage and crit, or spell damage and haste. This is consistent with the gearing philosophy early in BC, when we were generally presented with the same options, and it wasn't until T6 that we'd see 3/4 itemization types on one piece, and not until Sunwell did we ever encounter all four attributes on a single piece of gear (and usually it was only 3/4). For all intents and purposes, haste is truly only effective on Shadow Bolt, Haunt, and Immolate. GCD reduction doesn't even come close to cutting it, because in order for a DoT to do its full amount of damage, it still requires the full duration of the DoT. This is because haste doesn't affect DoT ticks. Ostensibly this is because haste affecting DoTs would make us imba in PvP, but I haven't ever heard a particularly good reason of why people believe this to be the case, given that our class is beyond broken in PvP at the moment (though that's a discussion for another day). Because Blizzard chose to allow crit to affect some-- not all!-- of our spells, currently crit seems to be the more appealing option when deciding between crit and haste at the moment. (Hit cap, as always, is a non-negotiable). But the problem remains that only UA and Corruption are allowed "DoT crits" through Pandemic. Immolate, Siphon Life, and CoA are still left out in the cold. Why is it that shadow priests are allowed to have all of their dots "crit," and yet we're given a half-assed version of that attribute? I always hate to say, "such and such class can do this, so why can't I?" because that disregards other glaring differences between the classes which affect playstyle and mechanics. But the fact is, Shadow Priests have SW:P, which hits harder than any other DoT in the game, and it's allowed to crit. Why can't all of ours?
6.) The "rotation" is disproportionately punished by breaks in dps. Affliction doesn't actually start doing any kind of significant dps until about fifteen seconds into the "rotation," when it's possible to have both stacks of SE, all your DoTs ticking, and SB filler occurring. Whenever we have to break our rotation, either because of a stun, an interrupt, movement, a silence, or any other random boss mechanic that requires DPS to halt, we are disproportionately punished. No other class suffers from this difficulty. Shadow priests have a less severe version of the difficulty, given that they too have to get their DoTs up and ticking, but given that they have fewer DoTs than locks do, the penalty that stopping DPS incurs is significantly less serious.
1.) Change the debuff durations to fall more in line with one another. Bumping UA and Immo up to 18 seconds would help out a LOT because then they'd be similar in length to CoA, so all three of those spells could be grouped together in a "rotation."
2.) Increase the length of time on the Haunt debuff to 15 seconds, or remove the travel time. I can't tell you what a source of frustration keeping Haunt up is for me, even now. Even if you cast Haunt before the Haunt debuff is gone, the transit time makes it such that the debuff still falls off. This can be fixed by removing the transit time of the spell and having it immediately hit, such as searing pain and immolate do, or by extending the length of the debuff. Of the two, I would prefer the latter, but either would make a tremendous stride in the right direction. Shortening the cooldown helped, but not enough.
3.) Fix Pandemic. At present, Pandemic IS NOT AFFECTED by raid buffs. Whaaaaa? That's right-- the crit you see on your paper doll is the crit chance attributed to Pandemic. So the tremendous amount of crit we gain from buffs given in the raid-- I'm looking at you, Scorch!-- DOES NOT AFFECT Pandemic. This cannot possibly be working as intended. Please remedy the problem and if you're going to give us some DoTs that crit, at least have them crit according to the real crit percentage we should have.
4.) Fix Eradication. There was a lengthy explanation of the inadequacy of 3/3 Eradication posted a while back, the jist of which was that the internal cooldown on the ability makes the second and third points in the talent have diminishing returns on dps to the extent that the first point in the talent has over three times as much utility as the second and third points.
5.) Make Shadow Embrace stack between Affliction warlocks, or make it be refreshed by more spells. Keeping up SE is such a huge pain in the ass and it's so difficult compared to how it should be. Is there any particular reason why SE can't be applied by more spells than just SB and Haunt? I understand that PvP might make it such that you don't want it to apply every single time a DoT is applied to someone (although don't Shadow Priest DoTs work that way, again?), but it would be really, really nice if we didn't have to restart our rotation from scratch every time Shadow Embrace falls off.
(X-posted to the DPS forum)