Many players used to switch professions whenever a single profession provided a greater bonus for them or their group. To prevent this Blizzard decided to even out the professions with Wrath of the Lich King. The effective gains from each profession are somewhat close together, with a few small exceptions.

Jewelcrafters get their profession gains from unique epic gem. A maximum of three of these can be put into their sockets, making the Warlock able to tailor these stat bonuses to his needs.

A blacksmith, no matter if he's an armorsmith or weaponsmith, is able to add an additional socket to his bracers and gloves, gaining an additional bonus from the gems placed there. Just like back in Burning Crusade enchanters are able to enchant their rings. Leatherworkers, a profession rarely taken by Warlocks, are able to equip their bracers with a special fur lining. This lining is stringer than an ordinary bracer enchant and costs far less.

Inscription, the new profession with Wrath of the Lich King, provides some special shoulder enchant that are not only way better than the normal enchant, but you are spared from grinding reputation with the Sons of Hodir.

Tailoring, a very popular Warlock profession, and engineering do not provide the same benefits as the other professions. While tailors are able to embroider their cloak this is a very situational enchant and often worse than the regular cloak enchant. Engineering get some gimmicks and toys for their belt and gloves, but these are outpaced by the regular enchants for these slots.

Alchemists receive the ability Mixology, increasing the effect from elixirs and flasks and making them last for twice the normal duration. There is again an alchemist's stone which can be used as a trinket.