I don't consider managers to be the leader of software teams.

The best managers I've worked for knew how to navigate the bureaucracy and politics of a large company and had next to no technical talent.

The best leaders I've worked for knew how to get shit done. If anyone dropped the ball, they could pick it up and score the points.

Definitely there's a need for leadership outside the scope of management, but the paragraph just above the heading "What Servant Leadership Means for Software" gave me the impression that this article is about engineering managers.

I look for all of these things as well, and they are critical. But none of them have any relevance in a technical domain if the person who has them isn't capable of pulling more weight than anyone else. Management is only approximately a learned and transferable skill. At the end of the day, lack of capacity in the target domain will make any managerial knowhow useless.

Also to be clear, I'm not talking about software development in the mythical man month sense, but systems thinking and a facility with abstractions and math combined with the ability to make such ideas real. Such people have the power to lift everyone up to their level, guide the group along an easy path, and fill in the gaps in ability present in their team.

There is a reason that people learn martial arts from people who have developed skill at them, not those who are good at managing workouts. The latter will only teach you how to manage your workouts. If you want to learn an art, learn from a master. In technical domains the masters are the best leaders, and you learn from them in every sense.

Martial arts are an individual pursuit. Software development is a team sport, which is precisely where your analogy falls apart. The best boxing coaches are not the best boxers. The best football, basketball coaches, sure, they may have experience as players, but you don't see the best players consistently go on to become great coaches. That's because leadership and coaching is a different skillset. I agree with a lot of e folks in this thread that perhaps the best combination here is a good (servant) leader to lead the team as a group, and an individual like a tech lead to train up on technical skill.

Being able to "write (either code or ideas)" is critically important to communication.