Probably the most common comp you'll be fighting - don't worry, though, it's really not that bad for this comp. My partner and I first tried fighting this comp as a drain team, mitigating the Warrior's damage and trying to drain the Druid. However the Druid, without having any pressure on their team, is free to drink often, to combat this, we had a Felhunter out, which is quite easy for their Warrior to tear to shreds. After playing around in the 2050s for about a week and losing constantly to this comp, we decided to adopt a new strategy.

Pressure the Warrior. If the Warrior constantly needs heals the Druid isn't able to run away and drink or the Warrior will die. This allows the use of a Voidwalker, since you're not too worried about the Druid trying to drink if your warlock is doing enough damage. Keep all DoTs up on the Warrior (even Flame Shock, if possible!) and your Warlock needs to spam Searing Pain on the Warrior. Also Fear the Warrior whenever possible. Even if he's going to break it straight away, Fear him anyway. He's going to run out of cooldowns soon enough to break them, once he does, your Warlock needs to Fear him again (once DR is gone, and he can't break it) and then put up Curse of Exhaustion, and switch DPS to the Druid (if he is in range/LoS, if not, don't worry too much about it, just stay on the Warrior) for the duration of the Fear, along with draining his mana. You need to take this opportunity to drink.

Warlock Perspective: This last bit is of extreme importance. One of the biggest mistakes a Warlock can make is not Fearing the Warrior whenever he doesn't have a Fear immunity up. Even if you KNOW he's going to break it a moment later, do it. It's still a GCD he has to use, and a cool down he won't have access to again for 20 seconds/2 minutes. The amount of pressure that a Feared Warrior takes off of your Shaman, even if it's for only 2-3 seconds, is immense and game changing.

The opportunity will soon arise where the Druid is trying to get away to drink, and has left the Warrior low on health, and if you believe you can burst the Warrior down before the Druid comes back, this is when you should use Bloodlust, trinkets, CL/ES, etc. Don't let the Druid get a cyclone though!

Basically the entire idea of this is to pressure the Warrior enough so that the Druid isn't free to drink, and has to stay there and heal constantly. When he goes to drink (because he will need to eventually), or you can get a full duration Fear on him, he can't break it, whatever the situation is, if you think you can burst the Warrior down, take that opportunity and do it.

Don't underestimate the burst capability that a Resto Shaman can do. On a Warrior in Berserker Stance, I can do about 2.5k non crit from a CL/ES combo, followed up with Lightning Bolts. Along with Death Coil/Searing Pain and such from the Warlock, that is quite a lot of burst (or Death Coil/Fear on the Druid, for longer time on the Warrior.)

If you're going for a takedown on the Warrior, you have the Warrior at about <10% health and the Druid is around, you can still take this opportunity to win by having your Warlock continuing DPS on the Warrior, and spamming Purge on the Warrior (to prevent Swiftmends). Though, if it's at this point, you probably can't burst them down. You'll have to get a drink in, and just wait it out until another burst opportunity arises.

Obvious tips:

• Earth Shield on the warlock.
• Water Shield on you. If, for some reason, it ran out and you don't have it on you again, you're doing it wrong.
• They will constantly try to switch to the pet when it's out of LoS. You have two options – call the pet back, save it quickly, put it back on the Druid, OR, get a new pet. New pet is risky if they realize you're doing it, and proceed to interrupt you and then kill the old one. We greatly prefer just saving it.
• Purge buffs early.
• Get a Voidwalker out ASAP. If you need to, run into the warrior, and use Rank 1 FS to prevent the Warrior from interrupting your Warlock.
• Warlock Perspective: If a Warrior knows you're trying to burn them and goes into defensive stance to spell reflect and mitigate, don't forget that howl of terror is an AOE and thus unaffected by spell reflect.
• Warlock Perspective: When using a Voidwalker, remember that his AoE taunt "Suffering" gained a new bonus on the tooltip after BC that increases the miss chance of anyone affected by it for a base amount of 10% for 15 seconds. Don't underestimate the value of this when you're taking too much damage; a missed mortal strike is a big deal.