Destro Warlocks are really good against all classes in 1v1. Undead Rogues and some Frost Mages will beat you 1v1 however (3.2), otherwise we're really strong in 1v1's.
As said, the problem is melee in Arenas. Instead of focusing purely on the Warlock vs Damage -issue, I like to watch other classes instead.
Compare the Warlock to a Mage and you realize they take damage easier, but in the long run we're losing due to lack of mobility. What Blizzard seems to be struggeling with is to find a spell that's both unique and implementable for warlocks that will open up for a new play style. Instead of being PvP-tanks I'd love to have more of a mage role where my positioning/movement is key for survival rather than gear and damage reduction talents.
I really hoped for the Destruction tree to get a cool 51-pointer in WotlK which made us viable. Instead we got a lot of increased damage aswell as more damage reduction (Soul Link move up tiers/Molten Skin). So now we're still PvP-tanks but we compensate by doing heavy damage. It's bad design in my opinion.
What you are suggesting sounds like the Blizzard- approach and I never liked the idea of just increasing the survivability by a one-push button. That's what the Shadow Priests got and I'm fine without it. My suggestions would be to add a mobility -talent, or a new pet that helps out.
I've given a suggestion before about a blink-wannabe -talent. It wouldn't work just like a Blink, seeing as that would be a great bore. It was more of the style:
Swarm
Instant 30-45 sec CD
XX Mana
The caster transforms in to a demonic swarm flying 15 yards ahead, dealing '1500' damage to all creature in its way, leaving a shadow trail behind the swarm slowing all movement speed of affected by 50%. While being in a swarm the Warlock is immune to slowing and stunning effects.
This "swarm" would be like the Dreadlords when they die, a green light followed by bats(?) flying around. Also used by second boss in Mount Hyjal to reduce healing.
The slow I've imagined to be like a black trail on the ground, like a frost trap. If the melee chooses to chase you through it, they'll lose movement speed and can be considered scrubs. If they just strafe 2 yards to the side before chasing they're all in the clear. What's cool about this is that it could be a supporting talent, just flying through your healer while it's getting bashed to slow the melee so it could get away or something alike.
It wouldn't be an instant blink like Mages have, it would fly 15 yards over like 1-1.5 seconds. We wouldn't be slowable/stunnable but still take 100% damage, and remove existing slows. Whether it would be usable while stunned I'm not sure. It might have to be, but seeing as it could be powerful combined with Demonic Circle hopefully that wouldn't be the case. It's sort of useless against casters but would give us the mobility we need to survive for longer fights. And not just that, it would allow for a new gameplay for warlocks that sounds really fun for me.
The other idea I've had was to be able to switch souls or something with the current pet, but I won't go into that aswell, I've ranted enough in someone elses thread