Speaking as one of those crazy people that did take notes in the previous games, write casual essays on the game's themes and plot devices, I'll admit that I really enjoyed Metal Gear Solid 4.
That being said... yes, the game does seem to be tailored to the fans, or at least those that have played the previous 6 (plus expansion packs [Metal Gear, Metal Gear 2: Solid Snake, Metal Gear Solid: Tactical Espionage Action, Metal Gear Solid 2: Sons of Liberty, Metal Gear Solid 3: Snake Eater, Metal Gear Solid: Portable Ops, Metal Gear Solid: Portable Ops Plus), and one semi-AU GBC title (Metal Gear Solid: Ghost Babel)) Metal Gears, this game does go over people's heads.
Arguably, the comment could be made that it would be like reading the final chapter of The Return of the King before starting The Lord of the Rings, as the game is designed to finish the story of Solid Snake. Aside from a couple cop-outs at the end of the story, it does so very well.
Yes, the movies are rather long, and take up more than 50% of the time spent... operating the game (the word "playing" is hard to use in this context), and the "Quick time events" in the game at least won't kill you if you miss them (Dear God, imagine having a QTE at the end of a 45 minute cut scene kill you...). On the other hand, it is what we've come to expect from this brainchild of Kojima, and at Mr. Croshaw has pointed out, it's nice for people to deviate from their norms, but at the same time, don't break something that's working. If you sat through all of Metal Gear Solid and enjoyed the over the top dialogue and cutscenes, and went on to play the others, then absolutely, drop the $60 American on the title. If you didn't... I'd say either rent "Metal Gear Solid: The Essentials" to see what you're missing (or if you like it), or just put that money in a tin for Forced Unleashed to come out in September.