Booking and Writing in the WWE often overlap, so knowing wrestling history would help the writer understand the direction the booker is going.
On the other hand, I would trust a writer to come up with something original without having to go back to the cliches that wrestling people seem to rely on like Cornette's 'Rock'n'Roll Express' tag team formula and the Dusty Finish.
Then you get something "original" like a Porn Star, or a Pimp... original is not necessarily good; and cliches aren't necessarily bad. Hollywood has proven you can work a formula over and over again (coughromanticcomedycoughactionmoviecough) as long as you can do it well. There are plenty of formulas the WWE could use right now that they haven't used effectively in a long time. Besides, if a writer is unfamiliar with wrestling history he might come up with a brilliant idea about a rebellious, beer-drinking, foul-mouthed wrestler fighting an up-tight, corporate, authority figure... *cough* I don't see how not knowing the product you're writing for is a good thing.