I've never missed the morale rules. I don't feel that randomly rolling to determine if the baddies run away make much logical sense. Some creatures will run at the first sign of trouble, others when they know the fight has turned against them, and others just have to be put down like rabid dogs.
I don't quite see why morale rules work against that. Especially the Basic Morale rules, which has monsters that never run in it...
Morale might make more mechanical sense in a wargame, but an RPG doesn't really need it; it's something that can be adequately handled by a DM's judgement.
One of the joys of using a morale mechanic is that for games that are very interested in system mastery over storytelling, it allows the DM to simulate morale without being distracted by how the group is actually going. So, you don't make the monsters run just because the group is doing poorly...
Cheers!