Just got far enough in Civ 5 to have a more modern navy, frigates and such. Their effect against barbarians is quite a sight to see.
with Gods and Kings you would be running into Barbarian Destroyers and alike . They made the barbs respawn faster, upgrade quicker, and become royal pains really early. They also made it so barbs can spawn in sight and even right next to units, although that doesn't happen too often.