Apparently one of the ideas I put forward in the post I linked to in the previous entry is quite popular. That being the idea of swapping Demonic Sacrifice & Dark Pact combined with a change to Mana Feed.
Demonology's idea would be that Mana Feed would be changed to act as a source of mana renewal for the demons. The demons, gaining back their mana would both act as damage/utility *and* as a mana battery for the Warlock. This synergy between the Warlock and their demon is simply paramount to the Demonology tree so why not extend it? Demonology should thrive on having it's demon out and having synergy with it, not sacrificing it!
Affliction would get an altered Demonic sacrifice, because, well Affliction already has improved Lifetap, and having the best health leech abilities is better suited to sacrificing health for mana. This Demonic Sacrifice would only be a 10% damage increase(down from 15%) but also bestow a 10% increase to health/mana received, further reinforcing Affliction being the health/mana sponge.
Destruction, finally, would gain both a buff to Conflagrate and Shadowfury, with Conflag being changed to both a burst and sustained damage ability which would renew, rather than consume, Immolate giving Destro a new ability to use in raids, help their sustained damage in PvP and make Fire Destro just that much more appealing. Shadowfury wouldn't actually get a buff in damage, but rather would debuff the mob/player to take more damage, in PvP helping to focus train target(s) with both a stun and damage debuff, and in PvE would give Destruction some utility.
In conclusion, Demonology would become more synergistic with Dark Pact/Mana Feed and not have a nearly wasted 21 pt talent in DS, Affliction would have it's damage and mana/health stealing capabilities increased by DS and Destruction would move away from being forced to pick up DS just to spam Shadowbolt ad nauseum, and would begin to use DoTs(Immolate+Conflag) and debuff the mob more(Shadowfury) making it much more of a Warlock and much less of a "Shadowmage."