First, the soapbox bit:
That said, even though they're not particularly scientific, the -EX's we have are very highly-rated, interesting stories. Unfortunately, there are only 8 of them, and the last one that's still listed was posted in December of 2012.
I understand if this was a fad that mostly passed after a contest, but it's still a format with a lot of potential, and something that, at least hypothetically, a lot of people care about. It also makes some sense if this was swept aside after neutralization logs were tossed out, if that's the case. I also understand that the format is inherently restricting, especially as both the base SCPs and their explanations would have to withstand current community tastes.
But, you know, isn't the challenge a big part of any contest?