I haven't actually played MoH: Pacific Assault yet, but some of the things I read in the IGN review stuck out in my mind. Despite the new capabilities of the MoH engine, you are apparently stuck on those gosh darn "rails" again, as JsARC pointed out. Also, the insta-spawning enemies seems really unnecessary to me, given that games like Far Cry can easily handle enemies miles away on the map. And the AI for your teammates is apparently quite dodgy at times, to the degree that they'll stand idly by while a lone Japanese soldier will run screaming at you with his bayonet. I can give that a pass in older games like Call of Duty, which in effect running on the antique Quake III engine, but for a "new" game that seems pretty unforgiveable. EA seems to be somewhat slow in embracing the gameplay that these new games can and should be capable of.
Still, I'll give the multiplayer demo a whirl. Either way, I have Call of Duty: United Offensive to tide me over until Battlefield 2 comes out.