About that withdraw ability on defend. I think i saw a defending unit move from tile to another as it withdraw from battle. Here some other ideas. Not letting Cavalry upgrade to gunship is reasonable. How about totally remake the Humvee to be successor of Cavalry. It can still have the ability to transport the personal but... i can think a problematic if it has not count as a military unit so now it possibly cannot move to territory restricted for foreign military personal. So basically it can be the fast strike anti infantry unit. Got a lot variate for promotions but still weaker that mechanic infantry and tank. About resources i will go somehow different way. (Dint remember if need a oil.) -But if yes how about give it option to Oil or Aluminium? (As a cases for electric engines and batteries.) Or alternative resources like coal, gas, prime timber(char coal), or (fat oil)from whales and seals, or gun powder(Extra experimental engine). And If it needs iron then again Iron or Aluminium or coper (if we want cheat whit Bronze) Upgrade cost will be a pain to count. (*not find jet*) If Humvee will be remade then RPG inflantry shall have at last +50% or +100% bonus against humvee. (dam those RPG are terror for those vehicles) Additional we shall make sure that RPGs have withdraw chance from battle. At last from attacking. Refinery, shall have ability: give this city has access to oil (if not have already) because it can produce a alternative to burnable liquid fuel. (Even Nazis during WW2 produce they alternative to crude oil.) (if not have already) Advisor page for see a dissent in other empires (cities). Maybe this can be a part of spi advisor. (if not have already) Religion Palace... Voting ability: vote for start one free tenet revolution (No revolution time). (Global.) vote for religion Unity for (5-10 turns * size of map * game speed) all religion type presented in city produce +1-2 happiness (Global.) Vote for word of piece (temporally all leader relation ship +10 points) (if not have already) United nations... Voting ability: vote for dissent solutions. All dissent meters in the world higher that stable are reset to stable. (Global) Establish world Health Care organization. +2 health and food in all cities on the world. (voting yes means you donate a % of founding cost) (Search for hospital, or Red Cross national wonder, on the world, then on list of the optional cities pick one where this building will be constructed. The city can receive a +10% research bonus.) Vote for found a International police. Lower chance to spread a syndicate, and a chance for event to wipe out syndicate from city. (need loyal or stable dissent level) For health/unhealthy and global warming event then options for solve problems by money, or troops dispatch, or city (whit one of these or near the event) will be busy(No production or income) if hospital or red cross are present in empire. Or pay a lot of money if those two are not present but WHC are present. Event Oil leak/ Oil tanker crash/ refinery accident, actual pollution on water. It will have a value of how hard it is as (amount of leaked oil) and based on tyme it can leak to another tile diverting some from its value. It can even polluted the land and possibly change the tile. (Same thing can be use to radioactive fallout. (Oh imagine you will nuke down the enemy empire and watch as how the fallout come for you.)) Will be there a new meter/bar/value indicated accumulated pollution in city? Then if it reach a certain level there will be a chance that a bad pollution event will occur. So you will need investigate a production to decrease the value or face the consequences of repeating pollution events. Like migration, pollution strike, dissent increase, production decrease, funding leak, improvident destroyed, barbarian raise, climate change. Tenet prayer +50% needs for doctor and scientist, change +15% to all GP but not for general and prophet. Or -25% Dissent required for level. (if dissent level needs 100Stable, 300Unsetled, 600 rebellious. Then whit prayer 75, 225, 400) Tenet meditation that give +25% need for train military units, change it to (if possible) +25% maintenance payment for army -1 strength outside the territory. Or 10% strength penalty. For ceremony i still see the +25% maintenance from number of cities as a somehow wrong. So probably force 1. trade route to capital and give it -50% penalty? Are there a tech that will give mountains +1 production? Like explosives or machinery as for mineshaft abilities. Or computers will be better options because you need calculate the oders to drill machinery.