This idea has been rattling around in my head for quite some time, and so I will attempt to be clear about what points I am (and, maybe more importantly, am NOT) trying to make.
My recent play through of The Legend of Zelda: Skyward Sword [a masterpiece, albeit flawed (NOT the point of this post)] brought this question back to the forefront of my mind... Specifically, what are the limitations of the video game medium? On this point I want to be clear: I am NOT trying to decide if video games are art. But every medium has limitations, and I think, in order to make something truly great within it, you must have an understanding of what they are.
My position is that video games are inherently limited in terms of narrative or story. Now, I really loved the story in Skyward Sword, and I feel it is integral to the enjoyment of the game entire. Further, I believe that the story in Skyward Sword could not have been told better in any other medium. On the other hand, can the same be said of a game like Uncharted 3: Drake's Deception? Here is a story that's been done better in film, namely Indiana Jones. Without a doubt, Uncharted 3 does an admirable (probably the best) job of emulating film narrative, but folks - lets really be honest here - it's still an emulation.
I do not want to pick on Uncharted 3 as I really enjoyed my time with the game, and there are many worse offenders. But it's precisely the fact that Uncharted 3 is a good emulation that proves the point better than highlighting a bad one (a la Battlefield 3's campaign).
I think there is a child in all of us that wants to be the star of our own blockbuster. These emulations have effectively granted us those wishes. Is it all we hoped it would be? Here's a better question: What are the limitations of film? Here's one: most films are roughly 2 hours long. Do you really want to be the star of a 10+ hour blockbuster? These are important questions.
Portal 2 is a perfect example of a video game which plays to the strengths, and avoids the limitations of it's medium. Is there another medium which could even present that narrative coherently? There is nuance in this medium which can be used as an AMAZING narrative tool. Take, for instance, the thrill of uncovering a story thread in Skyrim just by stumbling over a cave or discovering some new location, or finding a wandering behemoth in Shadow Of The Colossus. These are moments which are unique to video games, and validate the medium. This is a double edge sword however, because emulations don't validate the medium; they may actually invalidate it.
In conclusion, I believe there is a place for video games as art, but it does not continue by emulating other forms. As the industry matures I hope that more developers will understand the limitations of the medium and use it as an advantage. (CHEESY) It is here where you can feel and actually believe you are writing your own narrative; and that is a powerful source for art.