First my armory, maybe there is stuff wrong aswell.
I have huge problems, especially in arenas, to burst enemies down. As other frostmages dont have these problems (afaik), maybe i make mistakes. In the next games i will aswell try out Nether Tempest instead of Frostbomb to see if that helps.
So, what are you doing to burst enemies down? Is there a fix rotation?
First thing i notice, you dont reforge anything. Go for mastery, then haste, get rid of crit. Never ever use fire blast to detonate Frost Bomb, its something we used to do, but it took huge nerfs. So remove fire blast glyph, might aswell take out ice lance, its not a frost bomb spec glyph. You're not the class that does the AoE damage. The most important thing is to get the shatter effect on your frost bomb, its 3 ways to get this. Its by your normal frost nova, your pet nova, and deep freeze. It's critical that you get the timing right on your freezes. Our best burst looks something like this: Frost Bomb - > FrostBolt - > Pet Freeze - > Ice Lance - > Deep Freeze - > Ice Lance - > Ice Lance - Frostfire.
Use other CC's accordingly with your burst depending on what you're up against.
Dont frost fire bolt when opponents are frozen, use icelance instead or keep the freeze for peel. Dont waste finger of frost like with frost orb. If you roll frost bomb, dont glyph glyph of fireblast, instead let it tick out a nd make sure before it detonates everyone is frozen for max aoe damage. Or spec into nethertempest like most mages nowadays. Pet freeze on 2 targets+ give you 2 finger of frost. Same with frost orb, the more targets are getting damage the faster you'll get procs. Do frost orb on frozen targets and preferably when they are cornered or walled so its hard for them to get away. Glyph of deepfreeze removes the gcd triggered so you can macro deepfreeze with an icelance and preferably with your trinket for max burst. Best burst would be Trinket+icyveins, frost bomb > frostbolt > frost orb > pet freeze (while frostbolt is on its way) deepfreez+icelance macro, spam icelance frostbomb explodes, keep icelance spam with fingers of frost from the orb, and finish of with frostfirebolt proc. You'll loose finger of frost procs on the deepfreeze tough (waste).
If you're struggling i'd recommend going Nether Tempest instead of Frost Bomb. It's a lot easier to understand and play. Frost Bomb requires a lot more 'setting up' to be able to do your burst.
Nether Tempest just revolves around keeping NT on as many target as you can and icelance spamming into novas and using FFB procs every time they proc. Every now or then you could nova into ring or PoM ring someone, cast a shatter into them and deep as the shatter lands, shatter again and it'll drop them 50% health if done right.