it’s actually not really episodic. At least not in the traditional sense. It’s meant to be read as a single self-contained story. It was just released as a limited series, but that has more to do with the Graphic Novel not really being a viable form in 1986. Had it been written today, it would certainly have been released as a combined volume from the jump. Moore’s episodic fiction (Promethea, Supreme and Marvelman/Miracleman for instance) reads way differently than his epic stories (like Watchmen, Lost Girls or From Hell).

That said, Watchmen was intentionally written to make use of the medium of comicbooks. Basically it was Moore’s attempt to say “hey look, here’s some shit you can only do in comics that wouldn’t work in a book or a movie!” so there’s clearly going to be some problems translating it. If they’d allowed it to happen organically and rewritten where need be that might have worked better. In trying to be “true to the comic” and appease the fanboys, they ultimately ended up with a lot of crap that doesn’t work from a mainstream point of view and doesn’t really add anything to mythos from a comic point of view. It was just…. “Amusing”…

maybe.