There are some amazing aspects to the basic Musar path of Torah. Musar here means medieval books of Ethics like the Duties of The Heart and the rest of the basic cannon But we know that Musar was expanded after the Middle Ages and came to include about 30 books considered to be basic. [And many of the later works began to include kabalistic themes like the Mesilat Yesharim at least as an undercurrent.
Nefesh Hachaim certainly uses the Zohar as a source of evidence for his thesis that learning Torah is the most important thing one can do.
Other people [mainly baali teshuva in Israel] went to Breslov directly and that became their basic source of value and frame of reference. So when they later hear themes of the basic Musar books of people like Saadia Geon or the Rambam they think it is heresy.
There are however extra curricular sources which have important contributions to make concerning what human beings are about.
The question is how to find a unifying thread, A way to judge if a world view is sound--or if any aspects of it might be sound.This is not to say that once one has this thread his human problems will be solved. World view is only one important tool to come to where we need to go. It does not solve any human problems but it can be of some help not to fall into things that claim to be a solutions and yet are simply traps.
I have such thread that I use. Philosophy. But since the beginning of twentieth century philosophy the idea of philosophy being able to provide a way to judge other world views has become ridiculous.All twentieth century philosophy that is linguistic postmodern analytic philosophy- is in the famous words of John Serle "obviously false".
So people can be excused if they think my using philosophy to judge the validity of any given world view is unsound.
So what I have to add is that I mean I use the common sense, Maimonides, Plato, and Aristotle.
I have had to use my own sense along with philosophical studies outside of mainstream academia in order to develop my own philosophical point of view.