In regards to the frag belt, as opposed to simply building the individual bombs.
If you want to use the cobalt bombs every minute instead of the belt every six, go right ahead. The belt is far cheaper in the long run, which is the only reason I consider it superior to using individual bombs.
I have not run into any situation where the six minute cooldown on the belt has hurt me. I simply do not use it more often than that. I have some individual cobalt frag bombs sitting in my engineering bag, but they have never been used. The belt has proven to be enough.
It’s also worth noting that the belt and grenades only partially share cooldowns. If you use a grenade, this puts both the grenade and belt on cooldown for one minute. If you use the belt, the belt is on cooldown for six minutes, but the grenades are only on cooldown for one minute.
I say, use both. Default to the belt if it’s up, if not, then use an individual frag. Best of both worlds and it will save you some cash.
In regards to lightweave embroidery.
Bear in mind you are going to need spell penetration. You must have a lot of it, and it needs to come from somewhere. If you have 1800 arena rating or more, fantastic, grab the spell penetration gear and you’re basically good to go. True gladiator’s have a set of regular caster weapons and spell penetration weapons, and swap between the two as needed.
If you do not use the +35 spell penetration enchant, that must be made up for somewhere else, more than likely in gems, thus costing you spell power you would have otherwise socketed.
The embroidery itself is worth roughly 73 spellpower, assuming it procs nearly immediately whenever the ICD is up. Which is rather likely, mind you, with a 35% proc chance. Lightweave is a fantastic enchant (tailoring is considered the best raiding profession for a reason, and this is it), but bear in mind that it, ultimately, is a random proc.
+35 spell penetration will be with you for every cast, no matter what. Lightweave will not. It could easily proc right when you most need it; it could easily proc right when you’re forced to ice block to avoid death. The one upside is that you will, essentially, always initiate combat without it being on cooldown, thus you can basically always count on it to proc in the beginning moments of combat.
What would I personally do? I’d take lightweave, and just bump a couple spellpower gems for spellpower/penetration hybrids.
In regards to WG trinkets.
The spellpower trinket is the best one for any caster of any class. Whether you are a resto druid, shadow priest, or fire mage, you want the spellpower trinket. None of the others compare in any situation.
In regards to the resilience buff.
In case you missed it, the damage reduction provided by resilience is doubling in effect. Say you got 8% reduction before, now it’s going to be 16%. This means resilience is INCREDIBLY valuable, as in you could make a strong case for socketing pure resilience no matter what class or spec you are. PvP gear is even more important to wear now than it was before.
In a general sense, what this will do is slow down WoW PvP combat, something I approve of. However, this also means that it will accentuate the strengths and weaknesses of every class and spec.
For fire, this means that the tree’s inherent weaknesses (few and uncontrollable defensive cooldowns, no snare, etc) are going to be even more painfully obvious. If you pined for a snare before, now you will be in physical pain from not having one.
Killing healers will be much more difficult, and you will likely need to use every one of your interrupts to get close to scoring a kill on a decent healer.
In regards to why you want crit.
Yes, resilience reduces both your chance to crit and how hard you crit. However, there is no such thing as “stam/int/spellpower/resilience” gear. There just isn’t. All caster gear comes with some other stat on it, one of haste, crit, hit, spell pen, spirit, or mp5. You MUST choose one of those for every piece of PvP gear you wear, crit being the best option for fire PvP.
Note that you do require hit rating as a PvP mage. At least 4%, though 6% is better (as for some stupendously strange reason spell hit can overcome the passive spell miss chance racial abilities offer (less important for horde mages as we don’t have to fight oodles of blood elves)). If you cannot get the hit you need from weapons alone, you are going to need to use a hit piece somewhere. A neck, ring, or cape with hit is a good choice. Do not socket for hit if you can avoid it! You are wasting spellpower if you do.
In regards to glyphs.
The only glyphs I consider using for fire PvP are as follows: scorch, LB, evocation, polymorph, IV. I cannot fathom a use for anything else.
Polymorph is a strong contender and a very good glyph in its own right, and I definitely do recommend it if you’re looking for good glyphs. Ideally, you’d never have to polymorph something you have LB ticking on, but since when does PvP follow ideals? It can be especially good in situations where some DK decides pestilence is the coolest button ever, i.e. every time a DK does anything.
It isn’t my personal preference to use Poly, though I would seriously consider it for arenas and definitely take it if one of my partners was a warlock or death knight. You never know.
If you are using a fire PvP build that includes Icy Veins (absolutely nothing wrong with that) GLYPH IT. If IV is in your PvP build, no matter what spec you are, glyph for it. Always always always.
In regards to trinkets for you damn overpowered humans.
Pick the two most powerful DPS trinkets you have access to. Use those.
Raiding trinkets are excellent, use the resilience/on use spellpower WG trinket too if you don’t raid all that much. Put extra emphasis on trinkets with crit or spellpower, for example Muradin’s Spyglass is godly for fire PvP and Reign of the Dead is even better.
If you have access to 25man ToGC (heroic mode) using two RotDs is the best possible trinket combo. The regular and heroic version of this trinket stack, in the sense that each simultaneously proc fire motes, though they stack separately. This means you can’t have a pillar of flame firing every 4 seconds, but you can have two pillars of flame firing every six seconds.
And you wonder why I think raid gear needs to be banned in PvP.