Ya, I'm playing the priest as well.

For starters, the low survivability of an arcane mage is countered pretty good by a disc priest. I can pre-stack mana shield and power word: shield on all 5 and their livability is actually pretty high. Pair that with fire ward, spell steal, counter spell, slow, etc. I pretty much laugh at casters.

Warlocks are no exception, unless someone else has me distracted they get pummeled into the ground. In fact warlocks are among my first target as is any other char with fear. I always keep fear ward up on the priest and mass dispel is a .5 sec cast do get rid of aoe fears if i'm fast enough. Or I just trinket them. Also shadowfury doesn't effect me I can just blink out of the stun hit interact with target and start blowing instants while running at my target.

I'm not sure how to compare my burst with shamans. I'm not sure any other class in the game is similar to arcane mages. I can hit for 4K+ every 3 seconds with arcane barrage which is instant cast, another 4K with Fireblast every 6 seconds which is instant with no travel time. If I arcane barrage and then fireblast they all land at the same time for a near gauranteed instant kill. If I pop my cooldowns my damage just gets worse and if you give me a chance to stand still I'll just spam arcane blast which can hit for upwards of 15k PER MAGE at a fairly quick pace.

As for opening... I have a macro that hits my target with 2 spell steals, counterspell, slow, and dispel and cycles through which mage is counterspelling so its hardly ever on a cooldown. I hit any target with this as you'd be suprised what it does to some targets (even warriors hate getting silenced). So right off GCD one my target loses up to 4 buffs, 2 of which go to my mages, get silenced for 4 or 8 seconds and get their attack/cast/movement speed reduced by 20% and procs torment the weak giving me 12% increased damage on them. Then I pop arcane power, Icy veins, trinkets, and mirror image giving me 20+ mages that they have to figure out who is who, increased damage and haste. Then it all depends on the situation.

LoS is actually a huge bonus for arcane mages as all my damage is instant and arcane missles will track through walls. You get out for a split second for me to start an arcane missles and all 20 hits will track you down through a wall at 2-5k per missle for an easy 50k+ dmg. And I love hiding just around a corner so that i can nail people with a quick instant as they round the corner. If a whole group comes around the corner I can spam arcane explosion and holy nova for ~10k AoE per GCD while getting some minor heals too.

My big weakness for sure is 5x cloth armor. Melee hurts like crazy, especially in my current bad gear. Disc priests can pump out an enourmous amount of healing but playing the healer and 4x dps limits my reaction times. A good warrior can take me out in just a few swings or a single bladestorm if i don't have iceblock up.

Overall my favorite thing about this group so far is the mobility. Shaman may be better defensively but I can nuke very hard on the run with no special cooldowns and there isn't too many classes that can pump out the dps an arcane mage can if I get to stand still. I can't wait to see what this group is capable of when geared properly.

If nothing else it's extremely fun.