The thing that gets me is that if the idea was to make an intro episode that drew more on the things we learned later in the manga, there would be so many more interesting ways to do it, like (I'm biased but) laying some groundwork for Mustang & Hawkeye & Hughes as old war comrades who are in on some vaguely defined plan together. Richer context and character development that will pay off later, instead of unnecessary spoilers.

(And yeah, as it is, I also think the first episode is skippable, though I might advise going back for the Hughes parts later.)