Why are you expecting users to learn two new intertwined markups while you yourself were already ignoring the spoiler tag?

I'm afraid in the end this will cost more time to implement than time invested applying it.

As I said i'm in favour of adding an automatic JS toggle to long code sections and shortening them by default if they exceed a certain limit.

No one will need to learn new markup and everybody could adjust it to his taste in the display settings.

Same with overly wide code, btw.

Edit: Alone the spared considerations to edit those posts will help justify the investment.