I agree with the previous posters who stated that 90 (or 60) minute cut scenes are a step backwards for video games. As an interactive medium, it has an ability to go beyond just visuals, and do something original and unique. By just presenting a long cutscene, MGS4 is not doing much to separate itself from the world of cinema. This is disappointing as MGS was able to really demonstrate how video games can tell a complex story without resorting to classic exposition cutscenes - like the psychomantis battle. That was a beautiful moment in gaming, and cannot be reproduced in any other medium.
Overall, I don't think MGS4 is going to have the accessibility that will bring many new players to the table. I just started playing through the MGS series for the first time recently (finished MGS and 9 hours into MGS2) and this is the perfect series for GAFers. It's hard, requires patience, has a very intense and complex storyline, and constantly makes self-referential statements regarding video gaming. However, typical video game players are not GAFers. The long cutscenes filled with information related to multiple other games in a long series is just going to be confusing for most people.
Ultimately, I think Kojima had a chance to create a new video game legend like the original MGS by pushing for accessibility and playing towards the unique aspects of video gaming as a storytelling medium. Instead, it sounds like he went after fan service. This is great for the hardcore MGS fans, but I think it's a missed opportunity.
-G