Sticky Scandals, Teflon Directors
Gretchen Morgenson column welcomes probability that trial of former top Enron executives Kenneth Lay and Jeffrey Skilling will also drag former Enron directors back into spotlight; holds shareholders are too far removed from boardrooms and that Enron case is reminder of why they need to agitate for power in director elections; explores question of why corporate directors are welcomed back to boardrooms after being involved in notorious corporate debacles; photo (M)