I have a crude workaround that provides a 50% solution.
Under the Course Navigation settings I turn on the Search function.
Then I preview the course, select Search and enter what I'm looking for.
Rise will search the course and list all locations/lessons that have a matching phrase/word, and list how many times that phrase/word occurs in each lesson. If you follow the link to each lesson, Rise will highlight each matching occurrence.
EDIT: I open the same course in a different tab in edit mode, and when I find one occurrence in Preview mode, I make the change in Edit mode.
While you still have to go back to Edit Mode and manually make the replacement edits, the ability to find occurrences and locations is what's valuable to me.