This long-faced "average Joe" American comic would seem an unlikely candidate to become one of the leading forces in comedy in the 1990s, but his unassuming ABC family sitcom "Home Improvement" rose above the ashes of the fallen shows of the 1991-92 season to become one of TV's most popular shows. The premise of the Disney-produced series grew out of Allen's standup comedy act—a celebration and mild critique of man's obsession with machismo, power tools and impressing women. His likable if fairly traditional verbal humor was complemented and sometimes exceeded by an affinity for broad physical