The mage is the archetypal ranged DPS spell-caster. Mages arguably cause the most straightforward damage in the game, and have the biggest arsenal of instant cast offensive spells of all the ranged classes, allowing them to inflict great burst damage when combined with long-casting spells.
Mages are famous for their area of effect spells (AoE), such as [Blizzard] or [Arcane Explosion], that cause damage to all enemies in a given area simultaneously. When used improperly, this will result in a small army assaulting the mage directly and the mage’s sudden death. When used judiciously, however, AoE spells shorten fights, save group members’ lives, and make certain encounters easy that might otherwise be very tough.
Mages have other useful abilities besides their destructive spells. They have a quite useful crowd-control spell called [Polymorph] which temporarily turns an enemy into a sheep, pig, turtle, or even a penguin. This comes in very handy when facing multiple opponents, and in PvP also provides comic relief. Mages are also popular for their ability to open Portals for their party to use to travel to a capital city (Orgrimmar, Ironforge, etc.), and their ability to conjure water and food for faster regeneration of mana and health between fights.
Mages have particular weaknesses that offset their strengths. Their greatest weakness is that they are limited to cloth armor and cannot long survive melee combat, which they should avoid more than any other class. Their other chief weakness is their total reliance on mana, which limits the sustainability of their damage. Mages cannot do significant damage with melee or ranged weapons, so if they run out of mana they are relatively powerless (Wands might be useful for pumping out more damage while waiting for Mana to regenerate, but their DPS is pathetic compared to nearly all other weapons of the same level). As a result, Mages can be considered, in terms of play style, unforgiving with mistakes. Timing and awareness play a huge part in survival. In fact, while the Warlock and the Hunter are considered by some to be overpowered, the Mage is hardly mentioned, due to the Mage having among the lowest survivability in the game.
In PvE groups, the Mage should never engage the enemy immediately; instead they should allow the tank and other classes to wear the enemy down and build up sufficient threat. Once the enemy is suitably focused on the tank, the Mage will unleash a torrent of damage that quickly ends the fight. Knowing when to start attacking and how much damage to do is one of the main skills a Mage must master.
In solo play and in PvP, the Mage relies on spells that slow or freeze the enemy in place so it cannot approach within melee range. They have several escape abilities (e.g. [Blink]) that can help if they are losing a fight.
If high-powered ranged combat and mass carnage suit your tastes, the Mage is a good choice.
Thanks to: Gamepedia