I find it somewhat disturbing and amusing that a lot of the things I post for my fellow mages come out of the morons I've run into in the new random dungeon system.  So a quick shout out to Blizzard for putting the system in and giving men plenty material to keep me writing for years!

Today's topic has to do with one of a mage's more situational spells that's granted by talents in the arcane tree:  Focus Magic.  This 3rd tier Arcane talented spell allows the mage to put a 30 min buff on any friendly unit that will buff that unit's spell critical chance by 3%.  In return, whenever said unit has a spell critical hit, the mage gains a 3% spell crit chance buff for 10 seconds.  It is important to note that this only works on spell criticals, both to buff and to set off the proc affect for the mage.

Since you can buff any friendly unit, you can throw it on a friendly NPC if you like, or any player of your faction.  So long as that player/npc is in the same instance or zone as you and casts a spell that crits, the mage will benefit.  This naturally brings up the question of who to hit in any given situation.

Last night I was healing a random normal Lich King dungeon on the Ele/Resto shaman I'm currently leveling to 80.  It's well known that an Elemental Shaman is a mage's best friend along with Boomkin.  We have quite a few casters in our guild who aren't getting the benefit of either consistently in raids due to the majority of buff classes benefiting melee.  On top of that, I thought a shaman might be fun to try.

Anywho, we're doing normal Nexus and there were 2 mages in the group with me healing, a DK tanking, and a ret pally being an idiot.  We won't get into the details of how bad this group was, but the subject of FM came up via the less geared, clearly less experienced mage.  I offered my thoughts after he decided that the ret pally was the best choice for his buff.  But clearly, being a shaman in full heirloom gear, I was more of a noob and he continued to buff the ret pally because the ret pally had 4 spells in his rotation.  I chose not to fight with him further.  It was his own DPS he was stunting.

However, I felt it might be helpful to clarify for new arcane mages where this spell SHOULD go.  Looking at the mechanics of it, your first choice in any given situation is going to be a fellow arcane mage or another mage who has also taken the talent.  This is generally how my raid runs, all the mages daisy chain or share FM.  Please not that it only can buff one player at a time and the player that has it can only have one FM buff active at a time.  This means you can't have two mages throw FM on the same person and give that person 6% spell crit or two individual mages benefiting from one players crits.  It will only benefit the last mage to have buffed said player.  The proc will only activate on spell crit.  SPELL CRIT.  NOT MELEE.

Seeing as that is our number one reason to put it FM on a person, the rule of thumb is to put said buff on the CASTER with the highest probability of getting a critical strike with SPELLS.  Here is where the unbelievably stupid idea of the Ret paladin comes in.  Sure Ret pallies get spell crits; technically so do rogues, via poisons.  This does not make this a good idea.  Some damage from melee classes, despite coming from spells, count as physical damage.  This means the probability of your FM critting on a melee class is slim to none.  Paladins would get you an occasional exorcism, DKs might toss you an Icy Touch or Death Coil, Rogues a poison crit, hunters maybe a serpent sting?  Let's be honest here, you will benefit your group/raid the most by doing the maxing your DPS (all the damage and aggro avoidance aside):  in order to do that with FM, put it on a caster and save me the shame and head shaking.  The ONLY viable melee class on which to put Focus Magic is an Enhancement Shaman.  More on that later.

But which caster you say?  First and foremost, it's going to maximize your crits and that of any other mage in your group/raid by exchanging the FM.  When you do this, you get a nice roundabout of crits and up-time on the buff, plus you get a total of 6% every time you get a proc from your friend.  Since you can't put more than one FM on any given mage, if there are more than 2 mages in a group, you do a daisy chain, otherwise known as the "Mage Conspiracy" in my guild.  For example, if you have 3 mages in the group, Mage 1 will FM mage 2 who will FM mage 3 who will FM mage 1.  It's a nice little circle you make that is endless and happy and full of crit.  It also makes warlocks sulk which is always a good thing.

If you don't have another mage to FM or one that doesn't have FM, there comes a time of great thinking.  Keep in mind that DPS casters are not the only ones you can hit with FM.  You can also hit healers.  In an over powered heroic, this is usually not a fabulous idea because said healers are usually bored out of their skull doing things like tree-punch (I'm looking at you resto druids) or Holy Nova (ehem priests.)  If they aren't constantly casting at the same time you are casting, their chance of critting and procing your buff at an appropriate time is little to nill.  So in such a group, a DPS caster is a better choice.  Now, that's not to say you'll always have another DPS caster in your group -- a lot of times in my random heroics with strangers, I find no other casters but myself and the healer.  Thus the FM automatically goes to said healer.  However, this is where the enhancement shammy comes in.  Enhancement uses a complicated rotation full of shocks and procs for lightning bolt/chain lightning.  So if their crit is high enough, they're a viable choice.  How do you know if it's high enough?  You could armory them.  Or you could test it.

As for healers, certain healers don't do a whole lot of spell critting.  There's argument as to if HOT crits count at all for FM.  I haven't tested it, but if so, this limits a tree's viability as an FM target.  Disc priests are also a tough choice since a lot of their healing is actually damage prevention through shielding.  These are obviously better targets than a ret paladin, but if there's another choice take it.  Holy paladins are my favorite healers to put FM on -- they stack int and get a good deal of crit from it and crit all the time with their heal-spam.  The important thing to remember is that 3% crit, while lovely, is not likely to help a healer save a tank from dying better than better DPS output.  I had a mage tell me he had to FM his priest friend so "he can get those big crits to keep up the tanks" and was appalled since there were 2 other mages in the raid as well and we could have skyrocketed our DPS and made the fight shorter instead of hoping the priest could benefit from a measly 3% enough to not fail at tank healing.  On another note, the priest was holy and holy priests are raid healers.  Nuff said.

With DPS casters, it's also questionable if warlock DOT crits proc an FM for the same reason as a druid HOT -- both of these concepts actually place a buff on the target that do the critting, not the actual spell caster.  (Again, I have not extensively tested this data yet.  It's on my very long to-do list.)  So that leaves us with elemental shaman, shadow priests, boomkin, and other mages.  All mages love crit and it scales a lot better with fire and frost.  Frost has those nice shatter combos that keep your FM up and fire does it's living bomb thing which is full of critty fun too.  Elemental shaman have elemental oath that stacks up when they crit increasing the whole raid's crit on top of a lovely Totem of Wrath that adds to crit so you'll find them hitting up your FM procs too.  Boomkin also have a crit aura and their wrath-spam and eclipse give you a good chance at getting a proc.  Shadow priest are also a good choice as their channeled and direct damage crits will give you a proc.  In my experience, at level 80, any one of these will give you a constant up time of your procs.

Here's a fun flowchart for your convenience.  (You're a wizard Harry!)
For the sake of the flowchart, Enhancement shaman will be considered DD casters and tree druids will be considered the same as a caster using DOTs.  I plan to look into the HOT/DOT issue more in the future and I'll let you know what I find out.

Also, sorry this post is like... a week late.  My shaman just hit 80 and needed mad purpz.