If you look though, the Rus and the Horn is a trade, 4 damage for 4 speed. As it stands, the Longbow is a trade, 9 speed for 2 damage. Longbow should either be slightly more devastating, or slightly faster maybe. Longbow isn't bad by any means, but statistically, Rus seems really superior as a damage dealer, and Horn the best anti-archer / support.
I think the projectile update is awesome though. Ammunition is what you're firing, it only makes sense that it would alter the damage, and adds more versatility to your weapon. I just feel bad for the longbow: it wasn't nerfed by any means; everything else just got a really nice buff.
A suggestion - I want to see suction cup NERF arrows to stick on people for no damage, and I want to see practice arrows with -10 or -15 blunt damage.