Not overwhelmed, not underwhelmed...just whelmed.
The acting is not impressing me - and the origin - did it have to be another giant vortex in the sky? Haven't we had enough of those? I know the original lightning bolt has been retconned a time or two, and one issue in particular where it was revealed to be Barry himself traveling faster than light, creating his own existence as the Flash and becoming a paradox. As far as a dimensional breach goes - I'd like to think DC is setting up the concept of a massive multiverse, which is about the only trump card they could play over Marvel if they stretch it across their entire media universe. But I think all they're doing is establishing the origin of supervillains of the week, with that breach being to Barry what Oscorp is to The Amazing Spider-Man.
UPDATE: Hey, looks like the former TV Flash plays Barry's dad. That's very cool.
I think it's a shame the best performance in the trailer is from the guy who already has his own show. But you tell me.
Call me old but I'm still more partial to this:
h/t almost all of you