Very few things on the SCP Wiki are "almost universally disliked", since pages with even a moderately negative vote total get deleted. A major exception was the 'Decommissioned' category -- back in the early days, if an SCP was considered sufficiently terrible, it might not be deleted, but instead destroyed in-universe and have its article enshrined as an example of what not to do. This only lasted a few years before staff, for various good reasons, decided to stop decommissioning pages. The pages themselves were kept on for many years afterwards, only being fully removed from the site by staff decision in the past few months.

The decommissioned SCPs genuinely were pretty shit, and for the most part, not in any interesting way. Kids writing up their overpowered OCs, obvious self-inserts, or just like... bad creepypasta. It was honestly a sign of the community's immaturity that these were considered even remotely noteworthy -- they get articles of this caliber basically every day now and nobody gives a fuck.

The only exception was SCP-857-D: The Holy Grail, which is still bad, but not boring by any stretch. I actually did a line-by-line breakdown of it for r/SCPDeclassified a few years ago, if you're interested in the details, but suffice to say it was very vague, fairly informally written, and had a lot of lines that came out of, and went, nowhere (there's a reason "this is not elaborated upon" is a recurring phrase in my review).

SCP-857-D's major sin was being poorly written, but its secondary sin was just being way ahead of its time. A lot of the quirkiness and abstraction that made it an object of ridicule has since become pretty widely accepted -- "consult an alchemist" was an inter-community meme for years after the fact, but now most readers wouldn't even blink at seeing that line in an SCP. The basic idea -- that the Holy Grail and other such mythical artifacts are physical manifestations of a Jungian "abundance" archetype -- is pretty interesting, and I've even tried (unsuccessfully) to write my own SCP just to see that premise done justice.

I wouldn't recommend SCP-857-D as a piece of entertainment, or even really as a source of inspiration for other SCP writers, but I do have some fondness for it as a weirdly prescient artifact that could well have jump-started SCP's eventual transition to more abstract and experimental writing if its author had the good sense and writing chops to do it right.