Really? With that experience, they look like they could penetrate tanks.
No no no, they aren't supposed to be protected. Leaving 'em like that draws in the enemy heavy cavalry. Either set them on skirmish so they retreat and the heavy cavalry gets a face full of legionary with no charge bonus, or turn off skirmish so you can keep the enemy cavalry there while you flank 'em.As for horsemen, it's a matter of knowing how to protect your missile units, then you can put them to good use.