This kind of thinking really bothers me. They've gone to some pains to ensure their certification has some level of meaning, and now they want to chuck it all out the window based on the actions of a tiny minority.
Collective punishment is usually the product of lazy thinking.
I suppose I've always been of the opinion that they should offer the courses in a fashion similar to that of Khan Academy. I don't expect a certificate when I complete a section there as I'm there for the purpose of educating myself, not for accrediting myself. I think it's hard for Coursera to fulfill accreditation, but wish them the best if it's what they want to try for.