This post has nothing to do with pvp. if you are looking for pvp look elsewhere. Also this post may be kind of lengthy but it's detailed so you can actually try it in game.
Regarding mages in pve they really are fine. I've personally not been outdpsd on single target yet in any tier of dungeon and it gets great dps even before being super geared. So not being arrogant or conceited I just thought I'd post this to explain a rotation and how I play and get really high single target dps numbers.
I'm Necro and have been since beta 3.
Necro: 51, Warlock 15, Dom 0
I only have the warlock spec included because necro is 51 and dom being 0 its all and nothing.
Rotation - Read explanation after:
Using Skeletal Zealot as main dps pet.
Plague Bolt > Necrosis > dark touch > Looming demise > Grave rot > Last Gasp > Life Leech > rushing to full charge refreshing necrosis and dark touch as needed.
When the tank is counting down to grab the boss i time the cast of plague bolt to hit just after he engages. Then I dont use it again. I follow up with necrosis asap cause skeletal zealot does blood spike immediately when it reaches the target so I like to make sure I get the damage bonus from that with necrosis. Then theres a bit of a delay from when the pet does the next attack that gets the bonus from looming demise so I put dark touch on and then looming demise just in time for the triple hit. Now since the two deathly callings from Plague Bolt are about to be gone I throw grave rot up to keep deathly callings going.
While working on this rotation so far I'm keeping an eye out for opportunity procs to throw on life leech. Once life leech is up any other opp procs* I use to throw void bolt to refresh life leech and get bonus dps.
Now doing this rotation I'm also rushing to near full charge. Once everything initially is up and im at about 80% charge I exhume and pull out the 51 point mage pets which hit hard while making sure necrosis, looming, and deathly callings are refreshed for them and immediately switch to Lich form for the overall dps boost.
Now I dont waste any charge from here because I'm hoping for an OPP proc to cast empty the crypts which happens very often. When that happens I get nearest I can to the boss and bring out those 5 pets which all do a lot of dmg when you have 51 points in necro. So right now necrosis, dark touch, deathly calling, looming demise, main skeletal zealot, mage pet, second zealot, and 5 empty the crypts are destroying thsi boss. While the empty the crypts are running I'm spamming void bolt since I just refreshed everything prior to pulling them out. Once they disappear most of the time I still have enough time in lich form to get to 60% charge and soul purge for the last dps boost.
Then when all the pets go away and everythings on cooldown its back to the rotation (minus plague bolt) to make sure dots are up, callings are up, etc. Also debuffing the mob like the dwarves ice sheild, assisting with aoe on bosses with grave rot and corpse explosion, and more is a nice bonus.
I've never been outdpsd on single target in any dungeon run yet by any class. It might take some getting used to to coordinate all of this and time when your pets skills are gonna fire with proper debuffs up, etc. etc. but if you do it's pretty insane and consistent dps.
The reason I go 51 into necro is the 2 mage pets are really great, empty the crypts is actually really strong, and the damage boost of having so many points, plus pets being immune to any aoe is just really nice.
Any questions and flames are welcomed. Yes I know a brainless slug can play a rogue and do decent dps and all those arguments, but I dont think people who play mages long term do it because they like easy mode. And like I said.. I'm yet to be outdpsd by one.