We've seen two examples of emotive weaves...

1. The Crystal Throne emits something that causes anyone who approaches it to feel awe and wonder for the person sitting on it.

2. Osan'gar wove a complex weave which made Cadsuane and everyone feel awe and wonder when Rand walked in. It affected Rand too.

These could maybe be useful in battle. How about a weave that makes people feel terror, or takes away their morale? It seems that this weave affects the whole room and doesn't need to actually strike someone, like Compulsion or a shield does. The most obvious reason as to why it's not used is either that it would require a lot of power to cover a whole battlefield, and it affects everyone, so it could make your own men run away too.

Still, I think you could apply it nicely if you tried... you could target the approaching army, and make them feel scared. Or you could place the 'awe' weave on the hill where your leader and his generals are, so that any potential assassins hesitate or doubt that they're doing the right thing.