I decided to post an answer since some people might have a similar question about MOOC downloads, albeit not in relation to Coursera courses that will be taken down.
3 [legal] solutions:
- The best way to obtain Coursera content is to download it when enrolled. Coursera does allow the download of videos: "You may download content from our Services only for your personal, non-commercial use[...]" see Coursera T&C. Edx T&C reads: "the [...] video [...] on this Site are for your personal use in connection with those courses only". Bulk download of content can sometimes be against the T&C- I would scan the T&C before making any such attempt.
- Sign up for future iterations of the course that you wish to obtain. I have oftentimes enrolled in a course, not actively taken (or downloaded) it, only to see that the course was subsequently closed and I could not revisit the content again. By signing up for future iterations, you will be notified as soon as the content will be provided again. In my personal experience of using MOOCs for 4 years now, this is a useful feature that I have benefited from myself. Example: "Advanced Data structures in Java" was previously offered, then taken down, now re-offered: Course enrolment page
- Email the course instructors and make your case why you would benefit from the course content. My intuition would be that instructors will be bound by their institution's and Coursera's policies, but it doesn't hurt to ask. They might be able to re-direct you to other (future) courses featuring the same material.
Lastly, I wonder (and this is pure conjecture) whether the soon-non-availability makes the previously uninteresting courses suddenly appealing and a must-have. As mentioned above, Coursera does have a track record of re-using material and re-enabling access and it is possible that much of what is taken down will re-appear in the new system of specializations.