I don't get your story complaint. It's how BigBoss came to be and the origin of Ocelot and Eva. That sounds pretty needed. It's the beginning of it all. How MGS4's story can be enjoyed without 3 is baffling to me. MGS3 (and probably MG1) are the only ones that can be fully appreciated storywise without knowledge of the others.
And what do you mean "bleh" to MG1 and 2?
If you want to see what happens after MGS3, more of the whole big boss thing, you want Portable Ops then Peace Walker. And damnit, play them in order!
4 ≈ One