Aside from the people who actually get some inside info, 99% of the Internet only ever based their so-called theories about Wanda on HoM and some cliche crazy apocalypse maiden trope.
Which doesn't really hold much value for reference.
Well, I don't remember any of us suggest that, if anything, we only ever talked about Chthon being the power source like in the comics.
I personally hope they don't use Nightmare in WV at all, this cast is already as random as it can get. I'd like the villain to be more relevant to her own story.