Furthermore one constant criticism (which is valid) is that it doesn't seem developed, but I’ve also been told to keep it real short in that forum.
I'd imagine you're talking about the 400 word limit. While it might come as annoying, it's a general consensus that every article on the mainsite can be condensed into 400 words or less. It's ultimately how you choose to use your words - a general mistake I see people make is that they focus on frivolous, extraneous details that are of no use to a reviewer. While I can't speak for your idea specifically, consider focusing on things that actually matter, such as structure, genre, emotion, etc. An important thing to keep in mind is that the wiki is a collaborative writing site, not a monster manual. A reviewer won't pay any mind to whether your object is green or blue - they'll be wanting to look at what you want to do with it, where you want to take the narrative, what kind of story you want to tell.
Don't be afraid to take the reviewers' advice to heart and dramatically change your pitch. Speaking as someone who went through the greenlighting process also, I once had to change an idea to the point where it was nearly unrecognizable from the original pitch.
If you're confused on the fundamentals of writing an SCP, consider reading some of the Guides for Writing on the Guide Hub.
maybe an example of a recent greenlight would be great too
None off the top of my head, but you can check out some of the draft threads on the Draft Critique Forums from first time authors, which will likely include links to their greenlighted idea threads.
