They say a hero is only as good as the villain. If, by the same token, a villain is only as bad as the hero, then The Three Musketeers has, proportionately speaking, the best villains of any movie. Tim Curry and the diabolical Michael Wincott are inspired choices for Cardinal Richelieu and the Count (for some reason Captain in this movie) de Rochefort. In contrast, Charlie Sheen, Kiefer Sutherland, Chris O'Donnell, and Oliver Platt as Aramis, Athos, D'Artagnan, and Porthos, respectively, are like the Three Stooges without Moe, Larry, and Curly (i.e., Shemp, Joe, and Joe).
Athos, Porthos, Aramis, d'Artagnan; for those who have read Dumas's Musketeers saga, these aren't mere mortals; they are titans, demigods, princes of the Universe. Even The Man in the Iron Mask – an otherwise bad movie – knew that the Musketeers demand actors who can throw their weight around; in that case, Jeremy Irons, John Malkovich, Gérard Depardieu, and Gabriel Byrne (no points for guessing Depardieu's role).
Sutherland is the only film actor among the quote-unquote heroes; the rest are glorified TV stars. Sheen in the role of Aramis is simply outrageous; it's true that both the character and the actor are fond of women, but Aramis likes ladies and Sheen likes whores, and it's safe to say that the actor and the character make their conquests in very different circles. Moreover, Aramis has class, grace, and elegance; Sheen, on the other hand, has exactly what he deserves (this film was released just six years after Wall Street, but Sheen's career even then was for all intents and purposes over). As for O'Donnell, what can you really say about him?
Dumas's original novel opens with one of the best father-and-son heart-to-hearts in literature (although the gold standard remains Polonius and Laertes in Hamlet). At the beginning of The Three Musketeers, though, D'Artagnan Sr. is already pushing daisies; “my father was a musketeer”, boasts Junior; “the personal bodyguard of the King”, to which someone, quite rightly, replies: “the King was assassinated. Your father was a failure". If it's any consolation, at least he wasn't as big a flop as this movie (which ends on a very positive note, and not just because it's finally over; similar to its protagonists and antagonists, its official theme song is as good as the movie is bad).