Astroantiquity: I've been largely unimpressed with BDP. I'm always left a bit cold. He seems to borrow (and I'm using borrow loosely) from a lot of other directors, and you seem to think if he has any of his own style. I seem to think even George A. Romero is light years better than he is(although, Romero is a genre director he has his own style and he does have something to say which I can't say the same thing for BDP). Oh well, just my 2 cents.
De Palma has his voice. Call him at the very least Hitchcock without the Production Code style censorship; at best a prankster extraordinnaire with a voluptuous visual style capable of out-Hitchcocking Hitchcock (at least when Hitch is not at his best) and putting it over with a sense of humor and sexuality all his own.
Does he say anything? Does an artist have to (think the Marx Bothers)? Still, I think he does: in Dressed to Kill it's "Watch what you wish for," in The Fury it's "Sharper than a serpent's tooth is an ungrateful child," in Casualties of War it's "Truth will out" in Carrie it's "Hell hath no fury like a woman scorned." De Palma puts his own spin on these themes of course.
I wouldn't put him on the same level, but he has his place, maybe below Scorsese and Altman and Coppola and Kaufman (and, come to think of it, Burnett), definitely high above Tarantino and Richie and even Soderbergh (think about it: maybe the only Soderbergh that will last is probably The Limey and Out of Sight). Romero I'd count as an equal; De Palma has done more interesting work (as in more in number, not necessarily more interesting), but what Romero does few other filmmakers can touch. Well, maybe Pasolini, Argento...