Here's what Hollywood learned from last year's contentious Leo vs. Leo battle: nothing. Miramax eventually blinked and released Gangs of New York five days earlier than Catch Me if You Can, but that hasn't changed the outlook for next summer, when three multiplex heavyweights -- Paramount's M:I-3, starring Tom Cruise; the Universal vampire thriller Van Helsing (Hugh Jackman); and Warner's Roman epic Troy, with Brad Pitt -- are scheduled to open the same pre-Memorial Day weekend (May 21, 2004). ''We strive to pick release dates where we don't go head-to-head with other big titles,'' assures WB marketing president Dawn Taubin. But producer Brian Grazer -- who admits he takes ''the coward's route'' and moves his films when they're up against major releases -- thinks there's a solution: ''Greater collaboration between the studios.'' Now, that's fantasy.