Modern Germany is a product of a post-WWII occupation and re-education plan designed to make them unable to carry out offensive wars. I wouldn't pick them as my first case study on how to create an effective morale in the armed forces.

There is a pretty good argument that armies shouldn't be used offensively full stop, but looking at what America did after the civil war it is pretty clear that isn't the dominant philosophy. I've got no data, but by their nature invading foreign forces will tend to commit war crimes.