Chinese Unification involves a tricky mix of diplomacy and battle with seven rivals competing for the throne. And Omens is a scrap between the British, French, and Natives in colonial America.
Style and pace are varied, although all scenarios eventually come down to unsheathing swords. Each features unique units, buildings, technologies, civics and wonders. Warlords also includes special rules like the Mongol ability to camp and create units based on the surroundings (being nomadic had its advantages), and the Chinese family houses that spread bloodlines to other factions through marriage. The atmosphere is great; deploying units like the Macedonian hypaspists, researching the Mongol siege warfare tech, and building the Great Wall of China wonder is not only authentic - it lets you relive a slice of history.
And then burn it to the ground. Above all of the other rule tweaks, Warlords makes it easier to fight. Unit promotions come faster than in regular Civ IV and Great Generals (born in a similar fashion as the Great People in the original game) lead units into battle. Together they provide enough bonuses that you no longer have to worry about archers using killer city defense bonuses to wipe out a stack of elephants.