Here's the new capture code:
*Default capture chance of 3% set in GlobalDefinesAlt.xml. Does not apply to ground forces that can't move or starbases.
*Ground units can't capture if they are immobile.
*Promotions set with <bCaptureCounter> will defend against capture using the same percentage it has set for <iCombatCapturePercent>. If it doesn't have anything set for <iCombatCapturePercent> then it uses the default set in GlobalDefinesAlt.xml which is 60%. It's so high because at the moment only one promotion (security stations) uses it and it's not something too important that you'd use a level up to get it.
*There's a new promotion called Marines which does nothing and can't be gotten other than by units that start with it. It exists to let ground units use ground weapons by default. Other units can use ground weapon promotions if they first get Troop Pods. Invasion ships start with Troop Pods.
*Ground weapons now also add city attack, capture chance, and counter capture.
*Promotions barked as <bCrew> with be removed if the ship is captured unless the capturing ship is telepathic
*Capturing ship crew promotions are copied to any ship it captures.
*new promotions: Troop Pods, Assault Shuttles, Tractor Beam, Transporter, all which add 10% capture chance.
*Most promotions have 4% capture chance, Bulrathi, Elerian (also telepathic), Neutron Blaster, Ion Pulse Cannon, Achilles Targeting Unit, Trained Officers, Great General.
*Removed access to stealth promotions from starbases because they can't use withdrawal and I saw AI starbases taking them.
*The AI does now place value on the capture chance of promotions. Not much since the rest of it assumes the promotion makes the unit stronger, but capture chance only helps if you're already going to win. There's something in the unit building AI for pirate ships that checks the strength of other units before it's built that might be useful in this case but I haven't looked into that yet. Only units set to the "city attack lemming" scripts value capture counter because otherwise the unit should be trying to get stronger to survive rather than preparing for death and countering the small chance of capture.
Files changed: CIV4GameText_MOO2civ.xml, CIV4PromotionInfos.xml, CIV4UnitSchema.xml, and CIV4UnitInfos.xml where the only change was to give some free promotions as stated earlier.
So download the attachment, see how it works.