lol wat.
Mages are good, sure. But the second you get within melee range they're are dead faster than you can say "man, **** (opposing faction).
Take it from a guy who mains a mage.
HAHAHAHAHAHAHAHAHAHAHAH
There is so much wrong with this statement, Final. Mages are ridiculous in PvP, especially Frost Mages. Doesn't matter if the Mage is squishy when the melee class can't get in melee range to land a single hit on 'em.
Warrior charges in on you? Possibly eat a shattered Ice Barrier if the warrior hits the Mage hard enough (at the very least he'll be slowed just by hitting the Mage), Elemental Frost Nova (or you can just Frost Nova), Blink away, spam Frostbolt. Deep Freeze him, Ice Lance spam...ad nauseam. Oh, and maybe he'll pop Mirror Image plus Ice Block if he gets in trouble. Maybe.
(If the Warrior is smart, he'll use Shield Wall and Spell Reflect at key points in the Frost Mage's rotation, preferably when they try to Deep Freeze/Ice Lance. Even at THAT, though, Warriors have a helluva time staying on top of Frost Mages that do it right.)
Paladin comes at you? Pretty much the same thing as above, only a Paladin actually has a gap-closer (Hand of Freedom) that'll keep him trucking. Too bad you can still kite him just as easily as you can a Warrior. The biggest one-up that Pallies have, however, is their Bubble. It's much easier for Pallies to reset the fight in this way and keep going after the Mages.
Rogue? You better hope you can kill him in the initial volley popping out of stealth and/or that you're specced Subtlety. Otherwise you're going to have it worse off than a Warrior. Cloak of Shadows is your best friend here.
Enhancement Shamans? Not too bad. Drop Grounding Totems, Purge the Mage's Barriers, Wind Shear when they get antsy and cast spells, MAKE THEM TASTE THE FURY OF THE WIND A HUNDRED MILLION TIMES, etc. Not too much I can say here except that, again, they can be easily kited when all of their cooldowns are blown.
Death Knights? Anti-Magic Shell is amazing. Pop that and lemme just waltz right into melee range unimpeded. Drop your Rings of Frost, your Frost Novas, your Frostbolts...whatever. I'm still coming after you, as long as I have Anti-Magic Shell up. I also have a Mind Freeze and a Strangulate to keep your sorry *** from casting spells. Hell, I even have slows/snares (Desecration, Howling Blast, Chains of Ice) that'll make me force you to blow Blink preemptively so I can just Death Grip you back over.
My thoughts are a little disorganized at the moment, and I apologize for that. I didn't really get into other, more generalized specifics like popping trinkets/racials at the right time nor did I cover the other specs pertaining to those classes that I listed. I also didn't cover other ranged classes and what they can/can't do against Frost Mages. But, really, if ya'll wanna know anything just drop me a VM or a PM.
Edit: I'm not saying that Mages aren't squishy, but Frost Mages in particular have a lot of tools to keep them alive and out of trouble.
Smooth Criminal