as discussed on the recent "mega thread" on this topic started by JR himself - Berger was intent on getting the DRAFTS of the after action report for the millenium bombing from the Archives. it makes no sense to steal and destroy the final report, copies of those are everywhere.
why steal the drafts? its the drafts of this report - the ones that contain notes and comments - that tells the true story, the story about what was known about the extent of AQ operations inside the US before 9/11, who wanted to do something about it, and who did not.
I'm not sure there is any path available now to obtain those, or learn their contents, other then by inference. obviously, any leverage with Berger was lost when his case was sidestepped by DOJ.
The notes alone in those drafts must have been devastating. Maybe Bill and Hillary wrote "No" to any military plans to go after the jihadists.
Plausible motive. Only motive I've heard so far.