The argument for learning Musar is that it is hard to know what is "Daat Torah" without it. [That is to say that the idea of learning Musar depends a lot on the idea that the Rishonim [Mediaeval Authorities] understood Torah better than we do. And this principle to me seems clear even though it sees to be in danger of being forgotten.

And even if you have learned much of Shas {the whole Gemara} and Poskim [the mediaeval authorities that dealt with the Halacha] still to understand the world view of Torah can be difficult.

To me this all seems simple, but I have a hard time of conveying this message to people. I often go to the Na Nach place nearby and I can see the importance of Rav Nachman,  but why is it that some people do not see or at least emphasize the fact that Rav Nachman himself is building on the Rishonim? He is not coming up with a new Torah but rather deepening our understanding of Torah. (But to learn the books of Rav Nachman without Musar seems to me to bring about misunderstandings.)