Aptitude?
I am all for teaching problem solving skills but different people approach it differently - one size does not fit all.
That brings the question of aptitude into this mix; given that logical problem solving typically requires a particular type of mindset, are we going to saddle some children with a subject they will come to detest?
Case in point: when I was much younger (and dinosaurs roamed the earth) the teacher we had for logarithms (never forget it) went on about the exponent and the mantissa endlessly as if it was the answer to life, the universe and everything. While those are indeed both part of the notation it failed to get to the point or actually explain what a logarithm actually is. It didn't help that the teacher had a very strong Spanish accent (I have no problem with the Spanish but a dialect closer to the target audience is usually better). Totally put me off the subject.
Once I decided to look at it again because so many of the things I was being taught in avionics had logarithms, I looked closely and realised that logarithms can be defined in a way that takes one line:
If x = log(base a)y, then a^^x = y. The elegance of that appeals to me, incidentally.
There is an important part here; not everyone learns the same way or at the same rate so a 'standardised' approach is going to be a nightmare (as our education system already is) with two groups getting to detest the lessons:
1. The ones who pick things up very quickly. They will be bored o tears.
2. The ones who require at least 10 iterations to grasp a concept. They will find it such heavy going that they may just give up on it.
Having taught post secondary for some years, I can assure you that those groups exist, to a larger or lesser extent in every class.
Apart from the base problem solving, this should be an elective.