My point about machshava is that in the time of the Rambam, there may have been people with certain kashyas in their hashkafa, which are answered in the Moreh Nevuchim. However, the Rambam I believe holds that all yissurin comes from aveiros. I believe, in light of the Holocaust, where precious and pure little children were massacred, that that does not hold true. The main kashyas people have today are the misfortunes of the tzaddikim, and in the Rambam’s times, there were no misfortunes as great as what we saw in the Holocaust. We saw an entire continent of pure neshamos wiped out.
Second, many people have kashyas on the relationship of science and Torah. In the time of the Rishonim, science was practically undeveloped, and the sefarim of that time discuss the 4 elements, fire, air, water and earth. Different things were considered to be combinations of those four. Anybody reading the hashkafa works of those times will quickly get very disillusioned, as we know that we have much more sophisticated ways of describing nature (although there is far far more still to know that we do not understand.)
These are just some of the reasons why I don’t get much chizuk from these sefarim. On the other hand, my favorite mussar sefarim are Ish Tzaddik Hayah, and Tzaddik Yesod Olam about Reb Aryeh Levine. Holy Brother about Reb Shlomo Carlebach can also melt one’s heart.
Of course there may be general mussar concepts that one gets from these sefarim that apply at all times. However, I am referring specifically to Machshava.