The topic of Warlock specs came up yet again yesterday between my roommate and I (a common occurance considering we are both Locks) and while I am always a proponent of fixing broken / under performing specs, the end result was I'm fine with Destro doing the least sustained dps of the three specs. Whether all three specs need a boost or whether the dps difference is appropriate is a different discussion but, all things being equal, Desto should be the lowest sustained dps spec.
Our basis was pure dps classes can bring three things to a raid: Burst Dps, Sustained DPS, and Utility.
Right now, I think Locks are in perfect harmony if the numbers I've read are accurate. Each of the three specs shines in one of the categories.
-Highest burst dps (which is ideal is some fights), lowest sustained dps, and average utility.
-Highest sustained dps, lowest burst dps, and average utility.
-In the middle for both burst dps and sustained dps but brings the most raid utility via Demonic Pact.
People from all classes want all three specs to be chart toppers and sure certain specs will favor certain fights which is fine, but if Destro had the same sustained dps levels as affliction, the same utility (if not more), and far superior burst, why would anyone go Affliction aside from play style preference? This is the flaw mages (and other classes) have right now. Arcane has the best sustained dps, the best burst dps, and equal if not more utility than the other specs. Hence it is glaringly obviously why nearly all raiding mages are arcane. Add in the fact it is a very straightforward rotation and you almost have to scratch you head.
AoE is another aspect that could be noted but I think all the pure dps classes have comparable AoE. Some may be better but AoE is almost like icing on the cake, it is a factor but the heart and core of a dps class will always be boss performance.
Locks need some tweaking still sure, but I fully support maintaining this balance while tweaking the class and I'd like to see the same model applied to other classes. Some already have this balance more or less in place but those are mostly hybrid classes (Druids, Shamans). I think the biggest challenge for the pure classes would be increasing their "Raid Utility" spec so that they have something that contributes enough to justify having neither the highest burst or highest sustained like Demonic Pact does.
Just my 2 cents. Thoughts?