Just part of our industry from what I have seen over the years. It always seems to me that I am working with mostly technically competent people who know very little about anything beyond technology or their own personal experience in life.
Maybe this is true of most people (limited ability to empathize) but I think the intelligence and ego that many engineers exhibit to drive their performance impedes the ability to absorb information sometimes.
I like to write speeches for clarity's sake and then practice speaking them over and over again leading up to the event. At least a day before I shut everything down and let the chips fall where they may. It usually results in me getting all my points across clearly without sounding like a robot.
Forgive if someone has already stated the obvious, but the difficulty of rating the teacher profession, as opposed to other professions, lies in the intended outcome. For an engineer, there are many objectives metrics to measure code work against. The same is true for many non-programming corporate jobs (usual metric is $$$).
But what is the intended outcome of teaching?
Better test scores? (Google Scholar 'standardized testing and success' and take your side of the argument, but at best the jury is still out)
The three R's? Social development? Curiosity for learning? All of the above?
I understand your underlying point, but it is dangerous to contrasts teacher evaluations with other professional evaluations, lest we find ourselves programming students a science) and not teaching them (an art).
Crazy idea alert! With intended outcomes varying so much for teachers and teaching environments, I'd offer that teachers should be only evaluated by fellow teachers, parents, and students themselves.