The report paints a picture of a rapidly-snowballing disaster. Control was lost and the orbiter began breaking up less than a minute after Columbia's last radio contact with Mission Control. With the hydraulics lost in the left wing, Columbia pitched into a nose-high attitude prior to ballistic flight and breakup. The crew module depressurized through a fairly small rupture, and the crew would have been unconscious prior to the point where the module completely disintegrated. Depending on how long crew consciousness was maintained, they may have felt the violent tumbling of the crew module as it began a multi-axis rotation after separating from the orbiter.
By concluding this investigation with a lengthy and detailed report, NASA has laid the groundwork for enhancing crew survivability during a re-entry accident. For starters, the parachutes should be rigged to deploy automatically (although, in the shuttle's case, they'd only be used during a subsonic, level glide.) NASA should also quantify the current performance envelope for bailing out while wearing the current ACES suit. Of course, there's no substitute for making the shuttle, Orion, and other spacecraft so safe that the escape system will be irrelevant.