I am a warlock. Please don't group us up in "bringing raid buffs" too much. Most of us are Dest for pve.
We have a gimic in soulstones - but some of the above would argue that if you need these then you need a better guild (since they argued that your periodic raid healing doesn't make or break a fight..) And hell druids brez are better since you hardly ever know WHO is going to die (IC hard mode is nice with soulstones though).
We have healthstones..they could argue the same as above. Shouldn't need if you are good.
Summoning - well there is a stone outside if you want
Imp health buff is overwritten by warrior's.
We can get replenishment but don't always (and so many people can have it in a 25man...)
13% spell dmg at a loss of personal dps (but overwritten often by boomkins and less often by unholy dk's - we don't have any running unholy atm).
So..possibly locks bring some unique buffs. NONE of them fit outside an argument above that VE healing helping with raid heals and boss kills means you need a better raid. Any of the lock ones aren't "required" to win any fight either. It's about helping your attempts along. With healthstones a raid can use a dps pot instead (or mana pot).
I do this sp's need a tad more burst dmg (ive been thinking about making one..only caster class i don;t currently have an alt of). I see the playstyle much more akin to affliction. If the fight is short or you have to swap too much to an add that dies swiftly you lose dps cause dots don;t get time to tick.
This being said, our sp's are NOT bad. They rank high on many fights (remembering that fight style does usually depend on who is on top..don't try to beat an afflock on Yogg since we can dps with our backs turned more than anyone in p3)
Honestly I have only been in one guild that ran no sp (or boomkin) at all. It was the most caster unfriendly group ever! And I was only there a month (guild disbanded - was a hop between my home of 2 years and my current home).
The only time I would be willing to sit a sp would be if they were underperforming for their gear level or being numbnuts and standing in shit. The difference in the caster dps doesn't make up for a smart raider
Hope you guys get a little more burst/dps buffage, but wouldn't hold your breath on raid buffs that make you THE class to bring
I think the only two classes holding that distinction are shammies - Hero/bloodlust and a pally for Kings. Even then I've run without those before on nights where RL collided with the raid...