I think WCO gets tossed around a whole lot without any real definition as to meaning. People use the term as if it means one single thing, when it is a general offensive philosophy that numerous coaches have added to over the years. I also think the magical quality this philosophy is imbued with is overdone. Moreover, from what I can gather about the San Francisco Walsh offense at least, it was predicated predominately on man blocking rather than zone blocking with lots of cut backs. So people are making Denver stand-in for the 'WCO' when it is really the Shannahan variation on the offense. What you mean really is lots of stretch plays and cut blocking allowing the runner to find his hole and cut back if the lane is there. Does this correlate to what Seattle does (Zorn) or Tennessee (Smith)? Basically, why are we even talking about Denver's offense when that is not what the Redskins will be running? We don't really know what the offense will look like, and basically people throw around WCO without really defining (or knowing) what they mean by the term.
I also don't particularly like Paul Zimmerman, but I do like how he points out that the very term WCO is a misnomer since the term itself derives (apparently) from a quotation from Bernie Kosar that referred to the San Diego offensive tree that ran through guys like Norv Turner, Ernie Zampese, Joe Gibbs, Don Coryell, and Sid Gillman, and was only applied to Walsh through later misquotation of that story by some other writer(s). Anyway, I just like that, though 'West Coast Offense' obviously has become synonomous with the Walsh offense.
CNN/SI - Inside Game - Dr. Z - SI's Dr. Z: The real West Coast offense - Friday October 29, 1999 07:19 PM
Other useful quotations from another guy I don't love, but these points speak to my point above.
"Indeed, the West Coast offense that Walsh created has seen more spinoffs than "Happy Days," which spawned an entire subset of sitcoms. Even in a league where coaches insist there is nothing new under the sun, the West Coast scheme is arguably the most bastardized offense of the modern game, a blueprint smudged by years of alteration."
"Gruden prefers an I-formation or a one-back set to the standard split backfield that Walsh used and also relies on zone-blocking. In the classic West Coast offense, the blocking was primarily man-to-man, and the staple rushing play was the sweep."
ESPN.com: NFL - All roads lead to Walsh ... sort of