I think it's pretty clear which ones are good vs. not so good.
Wikipedia links to something obscure, which most readers won't have heard of before, about which there isn't necessarily a good general-purpose article or blog post out there, can be great HN submissions. Recent examples of good ones:
https://news.ycombinator.com/item?id=22880696 ("Dueling Scar")
https://news.ycombinator.com/item?id=22844118 ("Guédelon Castle" — but we probably should have changed to https://www.guedelon.fr/en/introduction_75.html)
https://news.ycombinator.com/item?id=22800433 ("OK Soda")
https://news.ycombinator.com/item?id=22622574 ("1% rule" – surprisingly, not previously discussed much)
A Wikipedia link to something well-known, for example that has been discussed many times on HN, or about which one can find an alternative article that goes into more detail in a less dry or predictable way, is not such a good HN submission.
Plan 9 is in this second, off-topic/generic class. Other recent bad ones:
https://news.ycombinator.com/item?id=22981218 ("Esperanto")
https://news.ycombinator.com/item?id=22927001 ("1989 Tiananmen Square Protests")