Lately, my view on what makes a good leader and what I'm trying to practice myself is simplifying down quite a bit. I've come to the conclusion that if there is one attribute you should optimize for, either for yourself as a potential leader, or in choosing someone to follow when selecting a venture, it's ... technical competence.
Hopefully it's clear that I'm defining technical competence broadly to mean deep knowledge about the details of your particular domain. I think this definition is applicable to engineers, attorneys, doctors, entrepreneurs, etc.
I think generalizable leadership attributes are important but purely supplementary to technical competence.