According to the Strategy Guide, elite and disciplined units who see lesser units routing receive 1/2 the normal morale penalty. The normal morale penalty can be as high as -12 for seeing two units of equal or higher level routing. Also, as hrvojej said, highly disciplined troops do not suffer any morale penalty from the general's death. The general's death penalty is normally -8 for a few seconds before dropping to a -2 long term penalty.