Halo, Assassin's Creed, Hitman: these are just some of the games that have hit the holy grail of franchising by expanding into mediums that the developers probably never anticipated when they made the first iteration of the series. You've got comic books, novels, shorts, and even full blown movies that spawned from something that was once viewed as nothing more than a mindless distraction that you played to simply pass the time. Of course, not every game series can have such good fortune and even then, things like video game movies have traditionally been horrible, but can Blizzard's upcoming Overwatch be the next game that spans mediums without being terrible?
Once more, with feeling
A major, and obvious, factor to whether or not a game can expand into other mediums (without feeling forced) is whether or not the story behind the game can be adapted for other forms of media. Something like Halo or World of Warcraft certainly has enough of a backstory for someone to lose themselves in, making them relatively easy to adapt to books and movies. True, the game itself may more or less revolve around a single character or event, but there is so much potential behind the lore that supports the game that you can explore (prequel and sequel games aside).
Fortunately, even though the vast majority of Overwatch's characters are more or less caricatures of popular tropes, there is enough to work with, especially given the universe's conflict between humans and robots (or Omnics, as they are referred to in the story) and how you can easily draw upon real world racial, political, and cultural influences to expand the story beyond the game. You can even expand upon the stories of some of the main characters and their relationships with one another but, naturally, some of them have more room for expansion than others.
Focus groups to the rescue!
Unfortunately, even if something might sound good on paper, it may not translate well to other forms of media simply because it might not catch people's interest. Let's face it, even though Hitman had at least two movies, was there really enough of a story to entice people to watch? After all, the premise of the games is that a clone becomes an assassin for hire and kills people: not exactly the most riveting or groundbreaking stuff, even if you are only considering the general gaming population.
Overwatch certainly can suffer from the same problem, seeing as how there are no new ideas under the sun anymore, but it all depends on whether or not Blizzard can take the source material and make it palatable to other audiences. On the one hand, they can make a potential misstep and focus their next big media project on the Omnic War, which would probably negatively impact how many times you can re-consume said media as it could simply end up being your next generic war movie/show. Or they could continue with the course that they seem to be taking and focus on the characters and how they interact with each other during the conflict a la Game of Thrones or Band of Brothers.
The 800 pound
gorilla scientist in the room
Ultimately, the viability of turning Overwatch into something that isn't simply a game is based on factors that are out of any individual consumer's control. As much as you may enjoy a long series of interconnected shorts that explore the universe of Overwatch, the fact remains that you will still have to vote with your wallet and your voice (and even then it might as well boil down to luck), unless you want something that either won't see the light of day or something that is so bad you would rather just forget that it existed.