Hi,
The majority of people using VLC would more likely not be familiar with CLI. As a professional documenter I have experience with having to physically travel to a programmer's desk and park myself there until I can get a straight answer that will enable me to write user-appropriate instructions.
That would indeed be far easier. It's possible to do that remotely if you have a specific feature you want to use through #EXTVLCOPT but it's hard to give a general answer given that there is no such "ready-to-use" documentation for that.
I also wonder how it is possible that VLC is being acceptance-tested without a table/matrix specification to check off. You know the answer, so you assume an casual hint will be obvious. It isn't.
VLC is a free open source project maintained by volunteers. My company is sponsoring development and in particular adding tests to provide acceptance in the review process, but in general the acceptance test as a product is done manually by the volunteers and hard-earned knowledges. In particular, the options are the first to not being automatically tested, mainly because maintaining the list of options somewhere together with a dynamic list of plugins that can themselves provide options, in addition with the multiplatform constraint is really really hard.
Ideally, the options would be extracted statically and the plugins would come with their tests, but that's not the case yet. And it's not even about documentation yet.
I think I have decoded your hint, but really this is a shortfall in the documentation. I have offered several times to help out since I have taken the lead in setting documentation standards, policies and procedures for multinational organisations (ISO 9000 compliant), but to a resounding disinterest.
Please note that on-going documentation effort is done here
https://docs.videolan.me/vlc-user/3.0/en/index.html with the contribution process being available to everyone here:
https://code.videolan.org/docs/vlc-user/
I'm not a professional documenter, so I don't really know how it works in your work environment, but you can probably propose workflow improvement or express needs from the upstream project here.