i believe that's an older version of vim. the latest one (7.2-0maemo7), which is probably only in -devel right now, is properly optified.
there's no "man" command on the tablet, so i guess all the man files are deleted in postinst. that way they still show up in the package file list, although they've been deleted right after installation. 'twas probably a quick hack, adding two delete statements in the postinst script is easier than removing the manual files