Unlike the terrifying changes patches added to games like you might expect from Blizzard Entertainment (I found Warcraft 3 to be almost unplayable the way they kept messing with stuff clear through frozen thrown each patch)... the Civ 4 patches actually help a lot of lacking areas in the game.
Just to name a few things recently for the Warlords patch off the top of my head...
- The Celts can make their Unique Unit (the swordsman replacement) with Copper or Iron (instead of just iron).
- Expansive civ trait got a build bonus for workers
- Aztec's Jaguar Warrior gets a free promotion that includes forest defense (instead of a jungle defense that was lost if you upgraded the unit).
- The AI Vassal intelligence check*
*I actually had to turn vassal states off before the patch because I got sick of an AI player down to 1 city constantly being a vassal to another nation who would then instantly declare war on me... even if they were a very good ally the whole game.
Honestly the only change I've seen as being kind of odd is siege units being immune to collateral damage. Siege engines are suppose to counter units moving in big stacks, but what if that big stack is all siege? Thankfully, that's only in warlords, so if you're still playing normal old Civ4 (vanilla) you have a very solid game on your hands when it's patched up to date.
