Fortunately, while all the research I've seen has suggested that it is critical to have different "tracks" for different students, it has also suggested that there is no need for the teachers/administrators to decide what track each student goes in. The results are actually better if you let the students and parents decide.
My high school was one funded by the Bill and Melinda Gates foundation and we tried to limit tracking as much as possible. For the first two years, there is absolutely no tracking. The idea is that the faster learners will help their slower peers who benefit from more interaction with their friends. Anecdotally, it seemed to work rather well but required students to initially be motivated to learn. My school never really had a problem with that because students applied to the school and could opt out of the application process without their parents knowing.
Anecdotally, I was always annoyed when I was dumped into a class with the slow kids and had to help them catch up while I was bored out of my mind. The 'no child left behind' mentality has slowed a lot of kids down instead of letting them learn enough to keep them interested in the material.
I'm a big believer of the theory that if you let kids decide what they want, they actually find a good path for themselves. I've been doing a lot of research on the Summerhill School in Britain, and it surprises me how radical that approach is, yet what logical sense it makes.
There are similar schools in the States (Carolina Friends school in Chapel Hill comes to mind), but most of them are very, ridiculously expensive (as much as a private college in the U.S.).
Can you link please to students/parents deciding tracks? I'm very dubious on this actually working, as if it wasn't for direct teacher/administrator intervention in my early education, I wouldn't have been pushed nearly as hard.
I think your experience is unusual in that you would have chosen easier classes left to your own devices. Usually, the debates about "tracking" center on the weaker students getting pushed out of the harder classes. What I remember seeing is that the countries with strongest schools (Finland and I think Singapore) just set a given pace for each class, and let students and parents decide what is best for them.