Please correct me if I am wrong, but it is my understanding that the community decided a long while ago (example) that if the question is looking for an answer which is so long it could fill an entire book or section/chapter, then it should be closed for being too broad.
With these questions and situations such as How big is too big for questions? where the stipulated requirements for an acceptable answer is unreasonably large, the ability to do this has gone now, since the old Too broad closure reason has been relabelled to Needs more focus.
This relabelling helps with questions which have more than one question or criteria inside it, and it is more intuitive this way, but it does not help with the situations I have mentioned above.
I propose that we have an additional "community specific reason" of too broad for this purpose.