After Ovitz: How Agency Hung Tough
Creative Artists Agency is locking horns with its founder, Michael Ovitz, and his new company, Artists Management Group; Creative Artists overcame what rivals saw as probable fatal blow--Ovitz's surprise departure four years ago--thanks to skills of its relentlessly ambitious agents and failure of competitors to step into breach; Creative Artists' battle to survive and its eventual clash with Ovitz has overtones of Greek drama, pitting young men against man whom they once considered fearful father-figure; photo; chart listing strengths and weaknesses of three top talent agencies in Hollywood: Creative Artists, International Creative Management and William Morris Agency (M)