When Alan Moore wrote the Watchmen in 1986/87, it was not only an exercise to explore the 'dynamics of a post-Hiroshima world', but also an attempt to prove that comics, then widely considered to be a form of low-brow art, was capable of dealing and portraying complex themes.
It was a wildly successful attempt; the Watchmen made graphic novels a serious form of literary art, winning a Hugo Award and landing a spot on Time's 100 Greatest English Language Novels from 1923 to Present. It proved that graphic novels as a medium was not only able to get across a mature plot, but show subtle nuances that was unique to it. Just like books will always be different from film, the Watchmen created a line that set comics into a medium deserving proper consideration, with its own singular literary merits.
There are many videogames that have been praised for witty characterization, engaging storytelling, visceral action and visuals. But the problem is, that's not the point. Books can do witty characterization, films can do visceral visuals, and even graphic novels can fuse them into a grand work. Having a fantastic game within the current paradigm of artistic expressions isn't enough. Moore's Watchmen was a feat simply because it tore down the limits of what was believed possible, and pushed the boundaries into a place that only comics as a medium could reach.
What videogames need isn't a game that is great by the current gaming/artistic/literary standards. What they need is something that pushes the boundaries, uncovering new places that can explore the unique nature of videogames as a proper medium. Instead of trying to emulate past literary greatness videogames should examine themes, stories through their own eyes, not a mash of narration and cinematics.
Lets hope there's a Watchmen for videogames to make them an accredited artistic form and allowing them more freedom and respect to pursue the more interesting, varied and less commercial ideas that dominate the industry now.
