Search inside a course is severely lacking. Presently, students have to know the exact title of a lesson (ie, choose an exact keyword from the title) in order to find what they're looking for.
In contrast, the community search is much more robust -- when you search a word, all instances are shown & highlighted whether they're found in the title, content/text, comment/reply, etc.
IMO this is an incredibly important need for students and instructors. It needs to be seamless to find a lesson containing that text anywhere, not just the title.
Because there are so many requests for improved search functionality, I may have missed any existing requests, so please forgive me if that's the case.