Personally, I'm for placeholders of
this type but against placeholders that just say "placeholder".
I think a detailed placeholder, like the one I created for Gardevoir, helps a lot with forming a good analysis. There I for example kept a list of all the moves that make Gardevoir unique, and listed down sets that (theoretically) have potential. If someone else were using Gardevoir too, he'd have a natural place to post his results as well, especially if he used one of the sets I theorycrafted.
A placeholder that just says "placeholder" though is still useful to some extent, but personally I would want to see a lot more effort on the OP's part before participating. One-liners may be quick to read, but they don't generate discussion.