Hello, Warlocks!
Let me start off by saying I'm not a Warlock, I haven't played one, and I doubt I will. Still, I found myself doing something theoretical about Warlocks, namely the talents Master Demonologist vs. Improved Life Tap.
The Definitive PvE Warlock Guide states that the best bet for a raid built is probably the 7/21/23, DS Ruin build where you spam Shadow Bolt (no debuff slots for Corruption ), but what if you went with a 0/30/21 Master Demonologist build?
This should give a plethora of options as well as an enormous boost to solo grinding. Not only does the Succubus only have to do 5% of the damage you do to outweigh the benefits of sacrificing her (as long as you don't need to spend GBCs managing her), but you can summon a buff as balls Imp if you're doing way too much threat, your Voidwalker if there's a raid-heavy encounter incoming (and your guild will love you on Garr), and even the Fel Hunter can prove useful if you need resistances!
Granted, on fights like Baron Geddon where pets can be an absolute hassle, sacrifice the poor Succubus! But could this not be a viable option, both for the raid and for being by yourself? If you're missing some Cataclysm, then take the points from Improved Lash of Pain, but the only drawbacks I see is having to tap 17% more, and not being able to use instant corruption when running by yourself. Granted, there may be important things I'm missing, but that's why I'm asking!
What say the Warlocks to this?
Edit: Correcting myself here: the VW boost is absolutely neglicible in raids. When would you be taking physical damage? O.o the Void Walker itself would like it though, if asked to tank stuff.