It seems that the removal of course and user Ajax settings has not been well-received at all e.g. https://moodle.org/mod/forum/discuss.php?d=208946, with ajax even coming up in an accessibility discussion http://moodle.org/mod/forum/discuss.php?d=212315
"It would be wonderful if we could get back the ability to turn AJAX on/off. I have several faculty - who do not use screen readers - but have trouble moving items on the main pages of their courses. Many of them have asked to have the "move to here" boxes back rather than using the drag and drop option."
An alternative to restoring course and user Ajax settings would be to have a drag and drop setting, as suggested by Dan P in the dev chat https://moodle.org/local/chatlogs/index.php?conversationid=11141#c384043