[Just for background for the public when I say Jewish Philosophy I mean you start with Saadia Gaon and go up until Crescas, Albo and Abravenal, (not Abarbenal) אברבנל comes from the Spanish and is pronounced Abravenal.]
The thing about Musar which is a bit hard to figure out is the Kabalah connection. I do not mean specifically the Ramchal [Moshe Chaim Lutzatto.] I mean rather that all Musar after the Ari borrows heavily and depends on Kabalah and especially the Zohar. And that tends to lead people off into all kinds of crazy directions. Yet it is standard fare in almost all Musar.--For Example, Sefer HaCharaidim, Reishit Chachma, the Shelah. If fact name me one book of Musar after that that does not depend on Kabalah? Only the books of the disciples of Israel Salanter himself.
Not that there is anything wrong with this Kabalah connection in itself. The Ari after all is good to learn when one is ready for it. But as a rule who learns Kabalah and is improved? No one that I have heard of except Bava Sali and people that were anyway into "Avodat Hashem" in a way that the Kabalah just added a bit to the intensity.
Kabalah of the Ari I see as simply a continuation of the Neo Platonic approach of all Jewish Philosophy from Saadia Geon until Crescas and Abravenal. Not only that but I see him as building a bridge between the Neo Platic approach of Jewish Philosophy and the Aristotelian Philosophy of the Rambam. This seems very good. What I object to are the cults that came afterwards. The Gra did well to excommunicate them. Not because of false opinions or character. Though both are evident. Lying and fraud are like bread and water to them. Rather the Sitra Achra is their essence. But not just any Sitra Achra but a very specific kelipa.
When I say the Ari was building a bridge I really mean the Reshash [that is Shalom Sharabi] the author of Nahar Shalom. Without his approach to the Ari, it is very hard to see any connection with Aristotle. The Ari at first glance seems totally Neo Platonic. It is only when you learn the Ari in connection with Shalom Sharabi that you can start to see how this approach incorporate Aristotle and the Rambam's Aristotelian philosophy along with it. If fact you see this clearly in the order of the worlds that the Reshash sets up after the revival of the dead. Right there he is switching from Plato's ideas to Aristotle's forms