I've been able to learn about the effectiveness of artillery first hand. I was able to invade a continent with artillery. Using 3 samurai (outdated, i know), 5 Infantry, 2 marines, and 4 artillery. I used artillery to destroy their (in this game England) railroad system with artillery and the Samurai, cutting off the city from any help. Then, after bombarding the city, I attacked with marines, followed by the infantry and took over a major city. I used Artillery a whole lot in that game because I was on a map of Japan, at the Southern tip of the island where there were many narrow straits with which i was able to hit enemy nations with artillery and not worry about the artillery being captured. My navy and artillery ruled the day. Goes to show that artillery is a really effective offensive unit.