Since combat rezzes appear to be considered mandatory by many raid groups, says Zarhym, Blizzard wanted to make the ability available to more classes. Certainly, this would fit with the modus operandi it's long had of granting abilities to multiple classes to allow for more flexibility in raid makeup. Zarhym also answered concerns that spreading battle rezzes would contribute to class homogeneity by noting that he's never felt like his warlock plays exactly like a druid, and giving warlocks a combat resurrection shouldn't change that. In fact, one of the reasons Blizzard gave battle rez to some non-healer classes was to avoid the threat of class homogeny.
While Zarhym says Blizzard hopes to have the change in for patch 4.1, it is still trying to get the code straightened out. Regardless, it looks it's only a matter of time now. As soon as Blizzard works out the kinks, we can expect to see yet another class with the ability to give raids one more chance to down the boss.
WoW Patch 4.1 is on the PTR and WoW Insider has all the latest news for you. From previews of the revamped Zul'Aman and Zul'Gurub to new Valor point mechanics to the new Archaeology items.