What is the most important pedagogical skill that physics teachers uniquely need?

I was surveyed by the writers of some pre-service teaching assessment, asking about the most important skills that teachers need for success in a physics classroom.  The survey, written in edu-speak, focused on content objectives and general science practices.

Thing is, the most important skill for physics teachers cannot be measured by a written test.  Do actors audition for Hamilton by taking a test?  "Which of the following does NOT describe the protagonist: (A) Bastard (B) Orphan (C) King of England (D) Scotsman"  "C." "Congrats, you got the part!"  

Good physics teaching is just as performative as musical theatre.  It is a craft which must be taught by example and by sharing tips, which must be learned by trial and error, which must be evaluated by diverse audiences over multiple performances.  

Okay, without reference to assessment or evaluation, then, what ARE the most important skills for physics teachers to know/learn?

Teachers need experience improvising in lab.

That is, firstly they need to know what equipment to get if they don't have a complete set, and to be exposed to new items.

Secondly, they need to help becoming virtuosi at using their equipment.  They cannot be intimidated by probeware, they need to know what a motion detector can and can't do, how to set up a jury-rigged flag through a photogate... in other words, they have to be able to go beyond canned instructions from a "lab sheet".

Finally, they need practice leading lab activities in all styles.  Most physics teachers I meet can set up eight lab stations based on a pre-printed lab sheet.  Most are not comfortable creating their own lab activity; most are not comfortable if the activity goes off book.  

In my AP summer institutes, I aim toward the goal of "playing" in lab.  That last day's activity, in which each teacher creates an experiment from scratch based on an AP problem, is the culmination of a week's worth of practice.  Teachers in my institutes all progress significantly toward comfort with improvisational lab work.

It takes the entire week, though, to change teachers' mindsets from following directions to becoming truly creative.  And even then, I've only changed the teacher's mindset; they often report resistance or even outright rebellion from students if they demand too much creative work too fast.  So the teachers next need help changing student mindsets.

I think I do a reasonable job helping teachers in the APSIs that I do.  But I can't work in their actual school community.  If I could follow up with teachers, I'd help them send this message of creativity in lab to their students, colleagues, parents, and administrators.  It's hard enough to get a student to try something without a clear path to perfection and an A; it's made nigh impossible if other authority figures are, usually out of ignorance, sending students a contradictory message.