A Tank / WWII Themed Action Focused Adventure Game with a Cartoonie anime art style.
Game would focus around being a semi open world adventure game revolving around using tanks. Major cities/locations will be based off historical factions from WWII. Players can buy/purchase uniforms, new tank chassis, upgrade/customize (ie pimp their tank). They can use their tank to hunt bandits, fight giant bosses that can be as huge as a land battleship. Players can rely on heavy armor/fire power of mobility and avoid battles all together, as you search and explore the world. You can find companions, and you can have up to 3 companions at any time. Companions are required for operating larger tanks.
For example: I imagine the start of the game would revolve around the player character (one you yourself get to create) he/she becomes a scavenger and his/her adventure starts when you're using a metal detector on an old battlefield (from the last war which happened not that long ago) upon which you discover a light tank (either a M4 Stuart or PzII counting on your character creation choices, ie you get to fill out some background history) From there you get a quest to dig it up, repair it, and get yourself your first tank, then your real adventure starts. =D
The game would incorporate every major country from the war, every city/province in the game representing one of them. Players can buy clothing that fit that culture/ethnicity, uniforms, infantry weapons (for segments of the game you fight indoors), and tank parts/chassis. So users can have a wide range of customization options for themselves and their companions. Tank Chassis come with turret slots that are restricted to L/M/H turrets, ie you can't put a heavy turret on a light tank but you can put a Stuart Turret on a PzII, or a BT-7 chassis, guns will be restricted in the same fashion. The game would also have unique parts hidden throughout the game. Like a PzII Ausf H open top turret, as well as an M8 Open top for the Stuart so you can mount larger guns on light tanks as a special reward turret. etc.
Combat would be based on Damage and Defense. Tanks guns will either rely on pure damage like a 105mm through 152mm howitzers, or defense penetration in conjunction with natural damage. A tanks defense will be modular based on the side you hit the vehicle in combat, or the boss. Some bosses win the game will have so much defense that you will only ever be able to defeat them with the most powerful howitzers or anti tank guns. And that is where the adventure aspect of the game comes in. It isn't story focused, but your adventure. Similar to say Mount & Blade you kind of decide where to go, when and do whatever you really wish. There would be some story but it effects the world more than you, changes things up through events, and even gives you an option to side with the bad guys in a final grand battle between an alliance of all the city states and this world conquest bandit faction. Tank types would mostly go like this. Light Tanks Rely on Low Health, Speed, and Low Fuel consumption, ie they're best for exploring, not exactly fighting, avoiding battles. Medium Tanks are an in between they're mobile but have okay armor and fire power, larger medium tanks are almost heavy tanks but hard to get, but not mobile enough to outrun other light tank MOBs, so they can't avoid all fights but vs the biggest most bad ass enemies. Heavy Tanks, need I say more. Counting on the chassis they're the least mobile vehicles in the game, but provide enough Defense that a lot of weaker mobs that would cause your starter light tank a headach to be more of an annoyance than a threat. Heavy Tanks have the Armor and Firepower when upgraded (ie best turrets/guns/equipment) can take on pretty much any enemy in the game without worrying of dodging fire. But they're expensive, consume fuel (you have to pay for fuel but they also get larger fuel tanks so). etc etc.
Though that's a dream. Closest example I can think of would be like crossing Metal Saga with Steambot Chronicles, but removing the JRPG focused story and have it more like a CRPG but with beautiful cartoonie visuals so the game will be insured to run gloriously for those action packed fights. The cartoon style I imagine would be more like Japanese films rather than anime cartoon shows, something like In this Corner of the World, Akira or any Ghibli film really.
Sadly, I know something like it will never exist, too ambitious.