Found some prior panzer threads - mabye we can use them as a spring-off board:
Panzer - by Mr. Civtastic
First you have to remember you need two tech from two different paths to build Panzers, Combustion (to build oil wells) and Industrializaton. Panzers at str 28 get 50% against armored units, making them 42 against 28 tanks. They can also attack twice in one turn, thanks to their inherent promotion of blitz. Their nemesis, gunships, are a couple techs off from Panzers, giving you a solid window attack without an equal. The best an opposing civ has to fight you is Marines. If possible, use the speed (movement 2) and strength of Panzers to fight your way to their oil supply and take out the improvement. Or better yet, capture the city. Now the ai cant build gunships. You could also pillage cottages to slow down his teching, and make an effort to take out any cavalry before they are upgraded into gunships.
Panzers, I believe, are also worthy of the pinch upgrade. With it, you'll have a unit that is stronger then mech inf (35-32) AND modern armor (42-40). So if you are strapped for money you can leave your panzers un-unpgraded and still have an advantage against future units. Upgrading them would give you a lead over gunships (50-48), but if you upgrade little to none of them you really arent losing that much. Panzers stand the test of time.
Panzers also have some synergy with Frederick. Frederick is Organized, which is faster factories. The German ub is the assembly plant, which can be built 50% faster with coal. Basically, Frederick can build REALLY fast assembly plants. My last game with him I could build assembly plants faster then FORGES in my new cities. I remember one city I was able to build an Assembly plant in three(!!!) turns. Quick assembly plants also means you can build Iron Works quicker. Assembly plants also lets you assign four engineer specialists (regular factory is two) for more production and to get a ge for iron works, three gorges, whatever. What does this all mean for Panzers? With those much-too-quick assembly plants, you should be able to build panzers extremely fast...definately before your enemy can have factories, even organized ai's. Same as Cossacks...get your first couple assembly plants up and running in your military cities, throw on pinch, and rule your era. Then keep them around to show the modern era that the German Tank is more then a match for them.
Panzer - by me (Thomas G.)
Replaces tank, gains a +50% bonus versus armored units.
Historical rant (delete this part):
Panzer is the German term for "Armor" or "Armor plate". Proper use of Panzers was instrumental in Germany's initial success in the early WWII. The use of massed armor supported by concentrated fighter/bomber support was first demonstrated on the western front in 1940. Dubbed Blitzkrieg or "lightning war", it was repeated with huge initial success against the numerically superior Soviet Union in 1941. After initial successes, the Germans decided to commit Panzer troops in street-fighting in Stalingrad, which enabled the Soviets to envelope and destroy the largest and best-equipped German army at the time, ensuring allied victory in WWII.
While the best German Panzers were far superior to the Allies' (the German tank ace Michael Wittmann destroyed 138 enemy tanks, which would have been impossible for any allied tank commander), the Soviet tanks were about equal in performance. The mass-produced T-34 was the best tank in the world when it was launched, which led to the Germans designing the Tiger and Panther tanks. The German success were due to superior doctrine of mobile warfare (remember civ II?), operational skill, and superior gunnery at long range. The Soviet army did not have much success until it started using Breakthrough tactics. Poetically enough, the encirclement of the German sixth army Stalingrad was the first such big-scale attack
Civ IV rant starts here:
The Panzer is unique unit which takes the longest time to be able to produce. You will need the techs of industrialism and rifling as well as access to oil (combustion). However this also means that in the late-game only Germany will have a qualitative advantage over other civs, as all the other unique units will be outdated.
While the +50% bonus versus armored units is a sizable bonus, it will only work against tanks and modern armor. Panzers will always receive favourable odds against enemy tanks regardless of where combat is joined, due to lack of defensive bonuses in tanks. Against scattered small stacks of enemy tanks, this should lead to the German player being able to kill enemy units while only sustaining unit damage. This will further lead to a great win/loss ratio, and can also lead to highly experienced and promoted Panzer crews. With medic units at hand, the rest and recuperation should not take too long. So panzer performs well as tank counter, without limitations gunships have.
In enemy cities most enemies will be gunpowder units with city garrison promotions, against which panzers will perform no different than the tank. Even if there are enemy tanks in defense, the game would almost always pick a gunpowder defender as "top defender". This means that the Panzer is no better than normal tanks in the taking of cities.
Panzers are unsurpassed in dominating the field surrounding cities, something a careful player can utilize in situations like home defense, surrounding a target city to cut of replacements and guerilla-type pillaging raids. They will also provide good stack defense due to bonus versus this era's prime mobile attacker. To avoid Panzers being left alone and unprotected a careful player can use road network in home territory, and counterattack in 1-move terrain only when in enemy lands. Mobility and morale can also be used to get the unit safely home after counterattack.
One final point about the Panzers is that they can still perform when pitted against modern armor. Not quite cost-effective, but a lot better than normal tanks. This could save a situation when the player needs a little more time, either to gain a source of aluminum or research the tech to build modern armor, or to build a last spaceship part.