It’s going to be a bit clumsy for maths and science questions - which sometimes require you to set out the problem in some detail, and can't just present the problem in its entirety in the title. It doesn’t make them impossible. But they will have to say "(see comment)" I suppose instead of "(see details)".

Here is a mathematical example, the author drew a diagram and uploaded it to show what it was they were confused about in a simple question about quadratic equations. It's now a comment of course.

If there is an equation 0 = ax^2+bx+c, why can't we conclude that the equation must not have real roots, even though it says that y = 0?

The main problem there would be that sometimes the question gets many comments so how will you know which of the comments the question refers to?

Also it’s going to be an issue for all those questions where the author wants help with some particular detailed scenario they are in. E.g. in my case, scared of fake doomsday news which they want debunked. They may put valuable details into the question. What exactly is it that scares them about the story? Though sometimes it’s obvious ,sometimes it isn’t so much.

SUGGESTED SOLUTION

Why not just move the question details into the comment section, as they are doing already. But do it as a special new type of comment actually labeled as “question details”.

So you can add the details but they are done in the comment section so hidden away. Make them communally editable also, as before. And the questioner can still say “(see details)” if they are essential to the question.

That would discourage use of details for unnecessary trivial distinctions, which would help with their stated aims - but without getting rid of them altogether for those who do need them?

Interesting suggestion by Joachim Pense - in a comment - you could add a comment and then just link to the comment as your source for the question. So that would be a way to add details just as before :).