It really annoys me too, which was how I came across this page. I always thought "big a deal" made more sense, because how can something be "big of"? If you say anything is "of a deal" doesn't mean much either.

I mean, fair enough if it is potentially correct, but it still annoys me :p No offense. It's like saying "couple things" not "couple of things"... I didn't thing "a couple" literally meant "two." I thought "A couple" was like saying "a pair."

Anyway, I appreciate the existence of different dialects, or whatever they are. I'm going to continue my search...