Let me preface this by saying I'm new here and that I'm going to have to apologise in advance for some peculiar spelling as I'm forced to use a non-English-language keyboard at the moment.
I've tried to acclimatise myself to the site, read almost all of the rules, read a bunch of SCPs and a bunch of forum material. There's a lot to take in. I think it's fair to say that you value quality and adherance to a certain tone, that you want the content of the site to remain broadly consistent. That's a noble aim that's kept the site good for a long time now, it's something to be proud of. It's also a barrier to entry for new members. There's a lot to take in.
I have a proposal that could help make that barrier less of a hurdle and more of a step:
On the front page, fairly prominently have a button for new members or stumblers-upon: An Introduction to the Foundation. Clicking on it takes one to a page with an overview (not an in-depth essay) of the site, the Foundation, the rules, procedures and such as well as links to other useful material. So far, so much like the Guide for Newbies, right? The only real difference so far is that it's made more prominent.
The Meat of the Message (AKA the Buried Lede)
Prominently on the page the link takes you to have a list of 3-10 recommended articles that illustrate what the site wants in its contributions. They don't have to be the best articles but they should be the best examplers of their kind.
This list should be refreshed regularly to avoid stagnation. I'd recommend that they be chosen by an annual contest for that purpose and only be chosen from among contributions within the last year.
This would allow new members or even just stumblers-upon-the-site to quickly get a feel for what the site is and what it cares about. It would avoid the feeling of dread at looking at 2000+ SCPs, etc. and feeling like you have to read them all to really fit in. It would also reward new contributions on a regular basis.