Right now, there are lots of spoiler warnings here in various articles. I'm not sure it's worth the effort.
Visitors to wikis of this type tend to not be the type of persons who are concerned with spoilers.
Several of the works are several years old. Having spoilers around for books that was published several years ago is needless cruft.
The spoiler warnings on this site are poorly executed, since they do not block the spoiler text and are not particularly prominent. The spoiler texts are also followed by non-spoiler texts (see e.g. Onyx)
The spoiler warnings break up the layout of the page and add visual cruft to it.
My recommendation would be to remove all individual spoiler warnings, and instead the front page should note that the wiki as a whole contains spoilers up to and including a specific work.
If something is deemed to require spoilers, it should be moved to a specific page, with a prominent spoiler warning on top of the page, like having Onyx/Onyx in Past Due