As a workaround, let me provide a 1 line tentative patch (moodle28-scorm-toc-expand-workaround.patch) that should revert moodle 2.8 to the old behavior of "the scorm TOC is fully expanded". It is provided just as a workaround, designed only to allow the survival of the users who find the current behavior too frustrating, until someone else provide a proper fix.
It does not conform to the "expand only the items in the path up to the current node" behavior requested in this ticket so you probably don't want to mainline it.
Make sure you clear your cache if you want to test the patch, otherwise the old JS file still get loaded.
In moodle 2.6, it probably will not work as lazy loading is done explicitly in mod/scorm/yui/build/moodle-mod_scorm-treeview/moodle-mod_scorm-treeview.js but you can probably change it in there. I don't know about 2.7.