Wouldn't the missile have destroyed the entire aircraft in midflight in an instant especially with fuel on board? Seems like a lot of debris clustered close together, plus the video shows fireball explosion as it strikes the ground which suggests the main body of the plane was still intact.
Could have taken the tail out, glanced the wing/body etc... causing the pilots to lose control and go into an uncontrolled dive? (no idea if that is possible - but would explain what you said).
Just need to wait for black box recording for that though probably