Earlier quoted context omitted.
Here is what I love to see: 1. An understanding of the fields of work and of their evolution. Don't look for candidates based on languages and libraries -- those might be OK to get an initial shortlist, but: a) Any programmer past junior level should be able to pick up a library (from a field he understands) in ~1 week and become minimally productive with a language in 2-3 weeks. b) It's the idioms of each field that…
I'm surprised I didn't find this higher up the thread: I'm soooooo sick of people hiring based on languages. It's right there in the first response in this article: "make sure you’ve included the same language as the job description if at all possible". This is so ridiculous. Either you're hiring a junior person and you're going to have to invest in ramping them up anyway, or you're hiring a senior person who will qu…
Just because you are hiring a lead doesn't mean it's a greenfield project with nothing established; even if the lead has freedom to migrate over time, that doesn't mean that it isn't important for them to be able to guide and mentor on the existing stack very quickly.
I generally agree the I industry overemphasized experience in using particular tools rather than skill in engineering systems, but it is not the case that specific tool (including language) skill is completely irrelevant.