I wouldn't expect it to happen until 6.0 at the very soonest. Assuming they can justify the resources at all. They said that 5.0 may be the last time they ever add new races. And considering all the work that's involved in fitting gear to models they may decide that filling out the other genders isn't feasible with their budget.

Personally I wish they had just picked one of the two races. But I can sympathize with their predicament of some people wanting a beast race and some people demanding viera and deciding to do a half race of both approaches.