I can’t wait for QUERY to become an official RFC.
It's felt quite awkward to tiptoe around the existing spec when building features that retrieve data; we've had to either use POST to keep sensitive filter criteria out of http logs or just create a usually massive URL-encoded query string.
Very timely as I just recently ended up with a URL query string so big that CloudFront rejected the request before it even hit my server.. Ended up switching that endpoint to POST. Would've liked QUERY for that!
And oftentimes some endpoints simply hit the max URL length limit and need a proper body. I thought we ought to already be using this method. Seems quite fitting for fulfilling GETs with bodies.
There's nothing holding you back implementing the QUERY method right now - HTTP methods are standardized, but not limited to the standard. Obsviously it depends how proxies/servers/etc. might handle uncommon methods.