Let's first break it down. You have about 1040 Fire Damage and 1040 Arcane damage. Those are the two options you have based on gear for yourself. Let's further see what you have without mind mastery. 927.5, we'll say 928. This puts you far beyond the threshold where your spec is a good choice.
40/21/0 will give you the oomph needed early on. But it scales poorly with gear. That's where 10/47/3 +1 and 0/47/11 +3 come in. They don't quite have the same raw power early on that Mind Mastery gives you. But once you start getting the spell damage to make Empowered Fireball work for you, they become powerful specs for raiding. There's a 10/47/3 +1 spec in the sticky here, and you can steal a 0/47/11 +3 spec from my armory
here.
Let's look at the first factor of why this is more scalable. You see, Empowered Fireball works on a stat you're constantly trying to increase. Mind Mastery, on the other hand, works on a stat that's incidental. Looking at your stats(we'll assume arcane mind when looking at Mind Mastery). You have 450 int and 928 spell damage untalented.
With Mind Mastery you gain 450 x .25 = 112.5
With Empowered Fireball you gain 928 x .15 = 139.2
That alone shows the scalability. The biggest thing beyond that available with 40/21/0 is Spell Power. Which will indeed work to improve the size of your crits(and ignites). But that is overridden by a 6% increased critical strike chance overall and a 10% higher increased damage to your spells before they've even crit. 10% higher non-crits effectively means that 110% x 150% = 165% damage on crits versus untalented. Considering 2/3rds of my spells are non-crits, that extra damage on non-crits really adds up.
I'm ignoring AP and Molten Fury. While not exactly equal, it's close enough. Same goes for Combustion and Arcane Potency.
Final consideration there is Elemental Precision, which is a 3% increased hit chance. Which is godly. It just is. With it, your hit rating from gear is decent. Without it, your hit rating from gear is low.
Additionally, your spec currently lacks Burning Soul. This is a nearly non-negotiable raid talent for a fire mage. Threat reduction is an extremely useful thing to have. And the pushback protection is also majorly helpful in any fight where you're going to take damage that will do spell pushback. Fights such as: Prince Malchezaar, Curator, Hex Lord Malacrass, Doom Lord Kazzak. Well, the list goes on quite a ways, actually. But you get the idea.
Let's talk about enchants. You've done fairly well here, but get those gloves enchanted. Also, for boots, I really only consider two enchants mage worthy(though I must admit even I have been lazy and have been using the much weaker version of one of them). The first is Boar's Speed. It gives both Stamina, which is good, and runspeed, which offers something amazing. In mobile fights, the faster you can avoid something, the faster you can resume DPS(or not die, which is also good for DPS). I have the version of this without the stamina. Again, because I'm a lazy bastid. The second is Vitality. 4 mp5 and 4 hp5 are excellent to have as a mage. The mp5 allows you to continue casting a bit longer, and the hp5 is just extra and useful.
Now, let's talk about gems. If you're serious about doing damage, there are 3 gem choices for you except under specific circumstances. Here they are in the order I'd gem them:
1)Great Dawnstone(+8 hit rating)
2)Veiled Noble Topaz(5 +dmg, +4 hit rating)
3)Runed Living Ruby(9 +dmg)
Until you are hit capped, only 1 and 2 are worth it. After being hit capped(or within a small amount of it) go with 3. I also spoke about special circumstances. These are:
1)You need a blue gem to either meet a Meta Requirement or to meet a good Socket Requirement. For these, go with a Glowing Nightseye(6 stamina and 5 +dmg).
2)You are roughly hit capped and need a yellow gem to meet a good socket bonus(increase to +dmg or a +2 spell crit or greater increase). For this, use a Potent Noble Topaz.
It's really that simple. Now, there are some minor exceptions with epic gems from heroics/PvP/token turn ins. Just use your best judgement there.
Finally, I need some info from you to proceed:
Are you finding yourself threat capped in fights? Is a paladin available(and giving you Salv)?
Do you die often?
Do you go OOM often? Do you have a Shadow Priest in your group?
Edited, Jan 18th 2008 12:13am by Poldaran