I'm a nice guy, so I rarely start wars in Civ. So I prefer the AI to declare ware on me so that I can whip them and grow my empire.
Warlords is great for that. In vanilla Civ I'd feel comfortable playing the builder and reacting to wars as they came. In Warlords that's not an option. If I'm not ready when the AI attacks, I'm doomed. It definitely seems more prone to war, although it may be mainly the usual suspects.
They come in force, they pillage, they raze cities.... I've prematurely ended two games after receiving a total whipping... on NOBLE.

They come in force, they pillage, they raze cities.... I've prematurely ended two games after receiving a total whipping... on NOBLE.