Minor Annoyance
Deity
You could always just let Govannon have his way with them for a turn
Since the Mobility promotion is unlocked with Horseback Riding, I always figured that the promotion actually meant that the units were actually going around on horses, or were carried about on chariots. Actual mounted units with the promotion just had better horses.
That's what I thought too, except that they aren't trained to fight while riding horses so they just rode to the battle and dismounted.