There's no reason to suspect the anger and alienation that fueled the rock world in 1991 is going to disappear over the next 12 months, which means an ideal emotional climate for Trent Reznor. Blessed with a brooding, obsessive stage manner that can make Axl Rose seem tame at times, Reznor--the leader of the industrial Angst band Nine Inch Nails--stole the show some nights last summer from heady competition on the "Lollapalooza" tour and he should parlay the success of the group's debut album into a Top 10 contender during 1992. "There has to be danger," he says, of his radical rock philosophy. "Rock 'n' roll deserves that. . . . Wanting to be a rock star (today) is as (safe) as wanting to be a fireman or an astronaut. . . . It's like being a doctor, only you get more girls to take their clothes off for you. . . ."