Yep, I'm an excellent programmer but I still don't fit the mold for a lot of the postings I see (not that I'm looking since I run my own business).
They are either insanely broad or insanely specific, which I think is insanely short sighted since you will either get liars or narrow your search down to those with only the exact skills you are looking for while missing candidates with more generally applicable skills.
If/when I get around to hiring my job post is going to look something like (off the cuff),
"Web developer wanted, experience equal to a couple of years building production systems any of the following a plus SQL, JS (any framework), PHP (any framework), Python (any framework), broad understanding of how the internet/web works, Linux experience (any distro)"
I'm not going to exclude an incredible candidate because they don't have experience of FooJSFrameworkOfTheWeek.js v9.1.2.11.2, if I have to go through 5-10 times as many CV's so what, a little bit of my time now will save me a shitload of time down the line by hiring the wrong person.