I think that Anita Blake, the "vampire hunter" character serialized by Laurell K. Hamilton, is something of a Mary Sue. She does not lack flaws, but she is idealized to the point where she does function as a wish-fulfillment fantasy in a very obvious way.
(I will note that Mary Sue is a sexist term for an excessively idealized character. The male counterpart is commonly called Marty Stu, but I think he should be called James Bond.)
There are two related reasons Anita is a Mary Sue. One, after the first few books in the series she keeps collecting more and more lovers, one or two per book at least. Two, and related, she has a wider variety of supernatural powers than anyone else in the series (with the possible exception of a sort of vampire goddess figure whom we haven't really met yet), and in each book she collects one or more new supernatural powers.
So Elise's post was about how disabilities affect her work, and people in the comments were talking about all the ways they have to work around mental and physical disabilities and how as they age they can no longer take certain abilities for granted and so on.
So I thought, Aging causes people's bodies and minds to lose one ability after another.
Anita, on the other hand, gains one ability after another.
Anita is a wish-fulfillment-fantasy antidote for aging.
It makes more sense to me now why I keep reading the series even though there are parts of it that really annoy me.