From a purely developmental standpoint:

Pro: Real-world environments and mechanics are familiar and save on the cost of developing immersion. For true immersion in a video game, which arguably helps "sell" the game, developers have to manage suspension of disbelief. With each step away from what is common and accepted as reality, the risk that players will lose immersion grows. If the player no longer feels part of the game world, she will be less likely to want to continue playing. By basing a game on the events of WWII, players know immediately what to expect, even if they're not a staunch follower of history. Situations, weapons, environments -- all are reassuringly familiar and easily accepted. The task then resolves down to mere mechanics: how to get the player comfortable with the interface and physics of the world. This is much more manageable a task.

Con: Endless themed sequels betray a lack of creativity on the developer's part. As a player, you may want nothing more than the same familiar experience, repeated with slight changes over and over. As a developer, you may want to rest on your laurels and provide that experience, leaving the innovation and risk-taking to other studios with more to prove. There is absolutely nothing wrong with that. However, there is a school of thought that states that not only is innovation good for the games industry, it's actually necessary for continued growth.

In today's age of ready accessibility, gamers have very few barriers to being able to play whatever they want whenever they want. While ostensibly a good thing, this can tend to make players impatient for games that excite their sense of novelty. And while there are of course games out there that provide new experiences -- Spore, LittleBigPlanet, etc. -- the preponderance of franchises does take up shelf space, crowding out those smaller titles that exemplify the innovative spirit, and miring the industry in sequel-itis. How many squad-based WWII shooters can one industry support? Is this a boom on its way to being a bust?

It seems, then, that the biggest issue with the concept of making games from real-world events lies entirely in the player's perspective, as it should. If you believe that video games are valid forms of communication, then certainly they ought to be allowed to comment on reality, just as movies do. The problem is that arguably most of the video games in existence aren't created with the goal of communicating a statement of critical thought. The larger question of ethics extends that argument to include the emotions of non-players and their perceptions of what a video game is and does. Each will decide for himself whether it's right or wrong to conceive of a cultural and societal event as fodder for gaming, and at this stage of game development it's still up in the air. As long as we keep the dialogue open -- to consideration, criticism, and even at times rebuke -- we will emerge at the far end a wiser audience.