I did not pay much attention to this while in yeshiva- even though I definitely saw this in most of the Medieval Musar books. This forms the basis for my approach about the importance of learning Physics and Metaphysics as the Rambam put it so bluntly.
The problem is obviously that these subjects tend to be hard. For that reason use the approach (I also saw in Musar books) of learning דרך גירסה just saying the words and going on with faith that eventually I will understand.
[Though I had seen this in only one Musar book [אורחות צדיקים] in California, later in NY I saw a book about learning [בניין עולם] from Bnei Brak that brought down a lot of Musar books that said the same thing. ]
The direction of the Rambam and Saadia Gaon was changed almost immediately after the Zohar was published. From then on this Rambam approach was relegated to the periphery, while mysticism took first place. My own approach is to accept the Ari and the Remak [Rav Moshe of Cordoba] but not to the degree of ignoring Saadia Gaon and the Rambam.
The main thing about the Ari is that whole thing has basically fallen into the Sitra Achra (Dark Side). It is almost impossible to get to the Ari without getting a fatal dose of the Dark Side along with him. It is for that reason I mention that anyone wanting to learn the Ari should only go to a descendant of Rav Yaakov Abuchatzaeira in order to avoid the Dark Side. [Or Rav Shalom Sharabi.]
The reasons are more or less because I saw plenty of people that took the mystic approach and was never impressed. I can't even think of one person I knew that was into mystic stuff that was not filled with religious delusions.