In the past, Warner-Lambert Co.'s Schick brand has tried a number of demonstrations of its men's razors in advertising, including one involving shaving a bowling ball. Now the company's trying a softer touch: a woman shaving her face to show how the Schick Tracer FX is gentle to sensitive skin. "You guys are so sensitive. What's the big deal?" asks French model Magali in one of three new broadcast and cable spots from J. Walter Thompson USA, New York. The campaign, budgeted at $20 million, broke yesterday.