https://youtu.be/gqW42BFqVjo?t=1812
"
Charm was always going to be powerful. If you're bumping into a group of say three orcs and you can take one of the orcs attacking you, stop him from attacking, and then cause him to attack something else, that is a huge shift in power.
And that's why charm was very very limited on who got charm, just straight up. Charm was a very powerful effect and one of the signatures of the enchanter. And that's why it would also break somewhat randomly.
And, you know, there were interesting things around how it was designed to try and combat how much you could rely on it and how good it was, and how much monsters would hate you after." - Geoffrey Zatkin