Then start doing the Shieldwall quests in Krasarang Wilds and buy the iLevel 458 trinket. While you are doing those, make sure you do the two heroic dungeons with DPS trinket drops every day (possibly also some dungeons with weapon drops). You get quite a bit of cloth doing these quests, so it helps with the tailoring too. Also do Golden Lotus quests and make Imperial Silk every day as soon as you can. Craft epic gloves & robe once you can buy the pattern from Golden Lotus.
Most other players in heroic dungeons probably have 460-490 iLevel gear. You are at 433.
Get enchants on your gear, make sure you have Lightweave on your cloak (it's dirt cheap).
Mages can expend mana in order to deal high amounts of damage with amazing speed, though they must be wary of exhausting themselves. "bull!@#$"
Area of effect spells:
By calling upon sheets of ice, columns of flame, and waves of arcane power, mages can effectively attack multiple foes at the same time. "Like any other classes"
A mage has many options for controlling the battlefield, from freezing enemies in place to transforming them into helpless critters. "true"
Mages possess the ability to transport themselves and their allies between cities and can summon replenishing food and water. " all ppl can do portals now"
More info: http://eu.battle.net/wow/en/game/class/mage
If the player knows everything about his/her class, I promise that he/she won´t have any further problems.
I know that fire might look a little bit "tricky", but nowadays, everything seems playable, although some specs may seem "behind average".