In my opinion there is too much didactics and too little common sense in teaching, particularly from the socalled professional didactics. In physics you should not teach old-fashioned outdated ideas, if the newest views are as simple or even simpler than the old ones.
One example is classical electromagnetism. There you have a quite simple set of equations for the fundamental issues of charges, currents, and the electromagnetic field. These are the Maxwell equations in differential form. Of course, you have to learn vector calculus first, but that can be done very well with the right physics pictures at hand, and electromagnetism is a great arena to learn also these mathematical tools.
This view is underlined if you look into the history of physics. One of the most successful (theoretical) physics teachers ever was Arnold Sommerfeld. I guess, it would be difficult to find someone else with more Nobel-prize winners under his or her students than him. If you read his textbooks on classical theoretical physics, you see that they were approaching the problems with the right mathematical tools and without unjustified "simplifications" but explaining the problems and their solutions in a very clear and concise way. It's an example for a very fruitful unity of research and teaching (the Humboldt ideal of university pedagogics).
Modern didactics on the other hand has the tendency to invent strange ideas of how to teach things. In Germany there is a big debate about the socalled "Karlsruhe Physics Course", which now is about 40 years old, but never has ever become a mainstream way to teach physics, because it is decoupled from the way the physics community is used to do physics. E.g., they do not start with good old Newtonian classical mechanics, which is the backbone of any start in learning physics (if you ask me), because they think that it's easier to think in terms of fluid-dynamical continuum ideas. So instead of forces they introduce momentum fluxes, which of course is not really wrong in the first place. Of course you can formulate all classical mechanics as fluid mechanics and with help of the various hydrodynamical equations (Euler-perfect fluid, Navier-Stokes viscous fluid, and so on), but first of all I'd not think that this is a good start for a freshmen to learn physics and second if you want to do it right, the math needed is much more demanding than the relatively simple ordinary differential equations, making up Newton's theory for point-like classical objects with forces acting on them, causing acceleration due to Newton's three laws of motion. In thermodynamics they claim, heat is the same as entropy, in electromagnetism they discuss magnetic monopoles right from the beginning although there is not the slightest hint of their existence. So it's well understandable und in my opinion very fortunate, why these "didactics" has not found many followers. Now the ministry of education in one of the German states wanted to introduce this (sorry to say it so harshly) nonsense into their (high) schools, and the German Physical Society was ask for a recommendation, whether one should do that. Of course, the committee checking this educational concept for scientific content and accuracy came to a very clear negative conclusion, strongly disagreeing to the whole concept to introduce physics to high-school students. Now a big debate is going on among the didactics section and the various other sections of the German Physical Society about this harsh but very justified judgement.
It's good to listen to Einstein, who said: "Try to simplify issues as much as possible but not more."
