Leaving out comics was totally an oversight on my part -- I'm a fan of the medium and have been beating the "they are too real literature!!" drum for many years. I agree with your expanded hierarchy, although I'd probably put comics and TV on about equal footing -- I think those forms of media both have a huge gulf regarding how respected they are based on content. We even have a name split showing the comic hierarchy: the graphic novel/comic book divide.

Was Citizen Kane a commercial as well as a critical success? Was it as lauded at the time as it is now? (I actually don't know the answers to these questions, and since I'm about to run off to work I don't have time to look them up.) I wonder how often these milestones are recognized as they are happening. I haven't played any of the three games on your list (and am unlikely to play at least Planescape because I can't do PC games -- RSI issues), but I have heard about ICO, especially, as being groundbreaking in terms of visuals. I look forward to reading your own, more detailed post about storytelling in these games, but now I really do have to go. Hope to have time tonight!