My belief is that mathematics does not necessarily need revising; however, what does need revising is who is teaching it and how it is being taught. It was my experience while in the school system, that there are many teachers in the math classrooms who are clueless about math, clueless how to teach it, and clueless as to how to get their students to understand mathematics.
I would love to see mathematics specialized or departmentalized at every grade level to include Kindergarten. We set teachers and students up for failure when we place teachers in classrooms to teach subjects that they frankly don't understand themselves. Teachers should not be teaching subjects that they do not know or understand. It's not fair to them or their students.
I was very blessed upon transitioning from middle school to elementary school. My first year of being in elementary school was quite frankly overwhelming. It was mind boggling to me how teachers were expected to teach the same students all subjects all day five days a week. I introduced the middle school concept of specialized instruction to my other 2 team members who eagerly embraced it and so did my principal.
What made it work so beautifully for our team was that one teacher was specialized in Reading/Language Arts, the other was specialized in Science and Social Studies, and I was specialized in Mathematics. It worked like a well-oiled machine!
The bottom line is teachers struggle with teaching subjects for which they are not passionate or knowledgeable. I know some of you are reading this thinking how can a teacher not know all subjects well. The fact of the matter is, when teachers are enrolled in college to earn their teaching certifications, they are not taught content. They are taught how to teach content and given strategies, pedagogies, theories, philosophies, etc of teaching.
So my vote is, instead of revising mathematics; let's specialize the instruction and put passionate, talented, knowledgeable math teachers in classrooms from Kindergarten - 12th grades.