So with lesser hurling the barbarian is using a small or tiny weapon, that I think does 2d6 damage if it's small. Does Deflect Arrows work against it?
If it doesn't, at what point does the Deflect Arrows stop working.
My personal thought is that the example of a ballista does 3d8, and 2d6 is well under that. I'd probably rule that hurling at 3d6 with a medium object is probably about the size that Deflect Arrows cannot cope with.
Lesser Hurl: As a full-round action while raging, the barbarian can lift and hurl an object up to one size category smaller than herself with both hands or two size categories smaller with one hand as an improvised weapon with a range increment of 10 feet. This inflicts damage as a falling object plus the barbarian’s Strength bonus. This damage is halved if the object is not made of stone, metal, or similar material. This is a ranged touch attack, and the target may attempt a Reflex save (DC 10 + 1/2 the barbarian’s level + the barbarian’s Strength modifier) for half damage. The barbarian may apply Power Attack to this attack as a one- or two-handed weapon, as appropriate.
Deflect arrows: Benefit: You must have at least one hand free (holding nothing) to use this feat. Once per round when you would normally be hit with an attack from a ranged weapon, you may deflect it so that you take no damage from it. You must be aware of the attack and not flat-footed. Attempting to deflect a ranged attack doesn't count as an action. Unusually massive ranged weapons (such as boulders or ballista bolts) and ranged attacks generated by natural attacks or spell effects can't be deflected.