Look, I know that I, a benighted Westerner, an automatic colonialist and an inveterate addict for ontological dualism (i.e., death-life, good-evil, now-then, etc.) am supposed to embrace enlightenment under the ancient hands of the East, but look:
Daoism is just dumb. Daoismus ist bloß dumm. 道家根本很笨。
Any philosophy that lives on the indifference to death as opposed to the "delusion" of the superiority of life, deserves to go the way of all flesh: in the dustbin.
Any philosophy, likewise, the dominant idea of which is to have no ideas (wu yi 無意) has no idea what's it's saying, and deserves even less effort trying to get such an idea satisfactorily (de yi 得意). The very idea (literally)!
Any philosophy that that argues for the hermetic provincialism of a never leaving where you are, deserves to be sequestered, quarantined, in its own hermetic unwisdom.
Any philosophy that idealizes the sealing up of all bodily orifices and, in parallel, the reduction of all inner fragmentation from latching on to other humans, deserves to be sealed up in its own monadic madness.
Any philosophy that actively promotes passive resignation to all states of affairs and all external influences, deserves to passed over as a mere act.
Any philosophy that argues one should accept all states as equally valid and preferable (since each states exist in se) while also arguing one should attain to the possession of all states in one's (own) unformed wholeness, shows itself to be wholly deformed.
I guess what rankles me most about it is that Daoism has so much good potential to illuminate and echo key Christian concepts but erases the subjects which should benefit from such wisdom. For example, the insistence on qi 氣 as an omnipresent, formative force echoes the transcendent nature of the soul (in relation to matter) in classical Christian anthropology. Likewise, the depiction of the leader as the least of these, and the depiction of the Sage (zhen ren 真人) as an infant and an elder, ring so true with Christ's kenotic victory, the childlike victory of Kingdom-life and the wisdom of God as the Ancient One. But by dissolving the personal subject (both I and Thou), Daoism eo ipso eradicates its own material and final causes for existing as a worldview. For as soon as the Ego (and the Tu) is erased, the coherence of communicating, or even holding, Daoism vanishes.
Like all absolute dualisms, Daoism falters on its implicit preference for the subject's good over the subject's loss. In the case of Daoism, a subject's "gain" would be to attain sagehood by releasing all plural attachments and personal ego-consciousness. His loss, by contrast, would be to remain in his infantile present condition as one who fears death, contemplates ides, etc. Even if philosophical Daoism (道家) is not as interested as religious ("practical") Daoism (道教) in attaining literal, corporeal immortality, nevertheless by motivating the pursuit of wisdom (qua the lack of fear of death or the attachment to life), Daoism eo ipso indicates an imbalance between value-states, which its "zero-perspective" indifference should reject. If all states really are to be viewed as equally valid and real, without any substantial loss of self, then even the state of not seeing reality that way should be embraced as whole and irreproachable in itself. As soon as the Daoist teacher reproaches a person for being unenlightened, all that person need reply is, "I am beyond your supposed need for change. I am already enlightened, because my relative immaturity is whole and valid in itself. To scramble for improvement would be to show I lack it. But to accept my need for Daoist improvement is to show I already have it."
The sort of fallacy to which Daoism falls prey is articulated at some length in Stanley Jaki's Means to Message (and here). Although Fr. Jaki does not, as I recall, mention Daoism, his "philosophy of adequate means" (as I would call it) signals Daoism's chief flaw, namely that its own claims cannot account for the means by which those claims are made.
Daoism does indeed have a number of good insights about adapting to change and feeling at home in each present moment. Daoism is, in that way, a great "tool" for handling discrete tasks. But as for a whole philosophy by which one lives? I deny it. But I reject it because it is the most ancient philosophy of cool; but as Edward de Bono says (in his book H+), cool is an immoral sham that erodes the warmth of human solidarity and the health of human integrity. Daoism ultimately boils down to saying, "Be cool." It's not as deluded as saying, "It's all good," since good has little meaning in Daoism. Daoism is beyond being touched, beyond being hurt, beyond being vulnerable. How, then, it can be so gripping and accessible to so many people, is beyond me. Daoism is Asia's Stoicism, as yet unbaptized. At least Buddhism insists on Love as the highest value, and Life as a legitimate good. Now if it cold free itself from its basic Daoist proclivities for indifference to any so-called "goods" in life, it would be a beautiful and existentially consistent worldview.
These recent thoughts on Daoism are stimulated by my current reading of Hans-Georg Moeller's Daoism Explained.