Badly MGS4 is the last game i will play of the series, you ask "but isn't that one supposed to be the last one?"
Answer is NO... Quoting from another web.
Though Metal Gear Solid 4: Guns of the Patriots may be the end of the line for Solid Snake, fans can rest assured that it won't be the last game they see with "Metal Gear" in the title. Speaking to MTV Multiplayer, associate producer Ryan Payton delivered the shocking revelation that a popular franchise would continue in the future. "I think there's been some misconceptions that this is the last 'Metal Gear,'"he said. "This is really just the last chapter of the saga of the Solid Snake story."
With Solid out of the way, what does the future hold for tactical espionage action? Metal Gear Meryl, the sneak-em-up with a softer touch? Or how about Metal Gear Soylent, the made-from-people masterpiece? Give us a clue, Ryan ... Ryan? RYAAAAAAAAAN!!
End of quote...
Do you know what this means? Take a quick look to the good games like final fantasy, pokemon and such... The same will happen >.< As long as people buy they will make even if all of them are epic fails. Not saying that MGS4 is but that the next Metal Gear games will be and mostly because this is the last one directed by Hideo Kojima and he's the one with the magic touch for this games xD. (God I gotta get outta the Other Games forum and quick =.=)
Oh, and to stay on topic, there's no way they will make a 90 frikken minutes cutescene, most of the people after about 5 minutes will go like "PRESS START AND SKIP IT QUICK!!!~"