Tactics for playing as/against Barbarians.

That's exactly right; almost all Barbarian heroes reach level 10 with expert logistics, making it not very enjoyable to run away from them.

Perhaps you meant the Pathfinder skill. I checked on 5 Barbarian heroes, and none of them received any logistics skills up to level 5, let alone expert.

Of course, with the Anduran artifact on the main hero, it's just extra experience.

Well, that's pretty awesome! Usually, you had to pass the army along the chain to whoever was closest, and then it was just a matter of luck. Finding such an artifact means winning the entire campaign. ;)

P.S. Checked again. By level 10, a Barbarian has advanced logistics at best, but in most cases, it's basic. The same goes for a Knight. :)