What I meant was more: You watch Snake on a bike. You play Snake on a bike. You watch Snake control rex, you get to control rex. Snake jumps on Drebins vehicle, you get to be ontop of it. Snake and ocelot fight -- you get to fight. Snake enters a microwave chamber, you steer him. Snake holds off the gekkos while Raiden and Vamp fight in a splitscreen similar cutscene. There were so many epic shit like the ones mentioned above and all of that was lacking in MGS3. I expected to be wow'd in the wrong way basically.
So in other words, you watch a long-winded cutscene and play the game right where the cutscene left off. I wouldn't exactly call that blending in or playing the cutscene; hell, every other game does this. The only games, apart from RPGs, that I would consider the player playing the 'scenes' are Uncharted 2 & 3 since it seemlessly transcends from gameplay to cutscene (and vice versa) at various times. Take the bar fight in U3 for example. You throw a couple of punches, then a short scene occurs, and then you're playing it again without even noticing. I admit; I didn't know for a few times if it was a cutscene or actual gameplay. That's one of the few things I liked about U3.
The only scene in MGS4 that I would consider the player "playing the cutscene" is the microwave scene. The mission briefings, to me, felt more like having a different camera angle, and you couldn't always control Mark in the mission briefings.