Buff to Warlock's damage - Details
As Ghostcrawler mentioned in the “Balance Adjustments” thread for 3.3, we would like to buff warlock PvE damage for all three talent trees. We have a few changes in mind we can share with you and welcome your feedback. That being said, of course these changes are not yet implemented and are subject to revision or reversal before the next minor patch.

Affliction: While some warlocks will no doubt disagree, we think the damage output of Affliction in PvP is pretty good. Therefore, we want a buff that will increase sustained damage after a ramp-up period. The specific change we have in mind is to allow Shadow Embrace to stack up to 3 times for a total of a 15% damage bonus. The current healing debuff would change to 10% per stack.

Demonology: We want to double the damage bonus of Demonic Pact granted the warlock. To avoid making this an all-around buff to raid damage, however, the damage bonus provided to other players would remain unchanged.

Destruction: We want to double the damage bonus provided by Empowered Imp.

As a further buff to both Demonology and Affliction, we’re testing out the effects of doubling the damage bonus of Improved Shadow Bolt in the Destruction tree.

Again, these are preliminary ideas. These changes might be revised or reverted before going live. Just the same, these are not necessarily the only changes we are willing to make and your feedback is appreciated. (Source)

Empowered Imp Buff
The talent would increase the imp's damage by 10/20/30%, up from 5/10/15%. The other effect of the talent would remain unchanged. (Source)

Demonic Pact Buff
At top rank, Demonic Pact will provide a base 10% spell damage increase for warlocks. The buff applied to party or raid members remains unchanged. (Source)

Changes in the next minor patch
One thing to keep in mind is that these changes are intended to be made in the next minor patch. It's much more risky to make drastic changes in a minor patch when we're concerned with it being released in a very timely manner. We're allowed to experiment more in major content patches when we have more testing time, including by the public.

Smaller tweaks to particular coefficients are better, more immediate adjustments we can make to improve the performance of a specialization without more drastically altering talent functionality with little testing. Taking that risk tends to lead to bigger adjustments in the other direction in the future, which is almost always perceived very negatively by the community -- as I would assume could be demonstrated by what you've written in quotes. We try to avoid the practice of "the devs giveth and the devs taketh away" whenever possible.

Another thing to consider is that we're talking about taking steps to keep all three specializations of a pure DPS class viable in PvE, even if it means some of these steps cannot, unfortunately, be taken in the next minor patch. There are other pure DPS classes a lot further away from having three viable PvE specialization choices. (Source)

Conflagrate changes
Hopefully this post doesn't get too buried in this thread since it's grown quite a bit since I last posted. Another change we'd like to make for Destruction warlocks concerns Conflagrate. We're looking into doubling the damage-over-time effect to 40% of Conflagrate's total damage, up from 20%.

As usual, I must warn you that this change is in testing and subject to revision or removal before the next patch goes live.