bsuiness analyst and domain knowledge

A recent posting came out in favor of the business analyst possessing significant domain knowledge in order to be successful. I don't know if I agree with this. 

Ostensibly a business analyst should not need domain specific knowledge to be a top BA.  What the BA needs is the ability to communicate well in all media to all receivers, and the ability to analyze and think critically: to question and consider.  These traits are hard to learn if you don't come by them naturally, but they can be learned. Domain specific knowledge is easy to learn.