Poor, poor Warlocks, how you must lament your role as the misunderstood badboys (and girls) of World of Warcraft. Sure, the SL/SL thing seems to work out for you, and Destro locks just can't seem to crit for less than 5k anymore, but if only people knew how hard it is to keep track of so many damned spells.
Truth be told, I love my Warlock, even if he's still terrorizing Azeroth in the forty-ish bracket. However, even by the time I got my Felsteed, I was wondering what to do with all the spells and abilities, I was rarely using some of them and wasn't happy with so many full actionbars. Around the same time, I was beginning to take notice that many Warlocks were saying the oddest things when summoning demons and their mounts. I wondered if there was a group of players taking part in a new "forget leet speak, let's just use grammatically questionable English" movement. I asked one about the random blurbs, and she was kind enough to point me in the direction of Necrosis LdC.
Okay, it was actually Necrosis back then (I need to level my lock...), but the idea has survived the test of time. Necrosis LdC is a circular menu addon that wraps all of your spells and abilities into collapsible menus much like Totemus. (To be fair, Necrosis actually started the whole circular menu thing, the Godfather of Sphere Mods so to say.) It will also manage your Soul Shards, warn you about different procs (Backlash, Shadow Trance), things you can do to your target (Enslave, Banish) or not do (target is immune to fear), and will show you a spell timer to track your DoTs, Soulstone cooldowns and more.
There's more, check in after the requisite break for some tips on using Necrosis LdC.