So many games these days are horrible shells - companies trying to half ass their way into a cheap sale with a cheap game. Games need to be detailed in depth and filled to the brim with content and experiences, targeted more so to the market of 'pro-gamers', instead of targeted at kids or 'casual gamers'. (Personally I blame the Wii for starting the trend that killed the quality of the industry). 

That being said, I always thought an amazing game would be some kind of huge Freeroam style WW2 game, based in Europe and Russia, maybe Africa as well. A huge living breathing game world that has so many different things you can do which then have a knock on effect to not only the local and national areas, but that can also effect the wars progression and outcome. Heavily based on real issues that would have faced people then – food, water, not being wounded, if so difficult to obtain medical supplies/treatment. Fragile characters who if not careful can easily be killed, forcing the player to either make a new character for the same game save or to restart the game and start again entirely. 

Half RP, half shooter and half strategy (yes that many halfs), choose your own starting position, area and country of choice. A few examples of the type of characters you could be;

A Russian arms dealer who scavenges the battlefields of Europe for lost and discarded arms and military equipment before selling them to the highest bidder. Hunted actively by the Axis, frowned upon by the Allies, friend to criminal elements. Hunts targets as a mercanery/sniper or generally serves the highest bidder. Runs a small team of specialists for scavenging/mercanery contracts. 

Or

German Luftwaffe pilot, young ace - ends up shot down over France and has to try and fight his way back home. Maybe ends up in with the French resistance somehow after he is assisted by a French family who are then all killed by the Nazi’s for their Jewish origins. He then ends up as a key resistance fighter sabotaging German fortifications, or maybe vice-versa he is still really working for the Germans and is feeding them intelligence and the positions of the resistance whilst trying to maintain his cover. 

Or 

Basic frontline troop, engaging in trench warfare and attempting to move his way up through the ranks by being the best solider he can be. Just trying to survive each day whilst bringing as much hurt to the enemy as possible. 

Or 

High up officer/squad commander, in charges of one or more platoons of troops. More tactical style of play, however still based on the one main character. Focuses on keeping his men alive and getting them better equipment or training. 

And so on and so on. 

You can’t tell me that with this new ‘next-gen’ that this kind of thing couldn’t be made. It would just take time, money and a lot of development. Something which never really seems to happen so much anymore.