Which courses have you taken? I've completed the Machine Learning course and I'm currently taking Cryptography 1 from Coursera. They both have been great.
Machine Learning, Drug Development, Nuclear Energy, VLSI: Logic to Layout, Computer Architecture, and Analytical Chemistry were all somewhere between "good" and "great" in my book.
ML and NE were aimed at non-specialists and weren't rigorous. Maybe that's the objection?
That's part of it, yeah, lots of courses out there but they tend to be things like survey courses, etc. Some of this is that the video content turns out to be the equivalent of only a 1 or 2 credit course.
It's unfair to criticize Coursera for having survey courses if they also have deep courses, which they do. It would be nice if they had more, but that's not really a criticism.
There's a Stanford professor that has the videos from his class about the Fourier Transform on youtube, go compare that to (just about?) anything on Coursera.
ML and NE were aimed at non-specialists and weren't rigorous. Maybe that's the objection?