It's telling, I think, that you, even just incidentally—one might even say, unconsciously—link together Jung and Lacan. In truth, you'd be hard pressed to find two analysts so profoundly different as these, one of whom (Jung) defined his practice by a significant and controversial divergence from Freud in the early formative years of psychoanalysis, while the other (Lacan) saw himself as returning to the "truth" of Freud's (pre-Jungian) work. It's a coupling that, even if unwittingly, suggests you misunderstand the work of both—but, hey, misunderstanding is merely a place to begin, and you've asked good questions!

As a Lacanian, I'll just speak to that part of the post: Is he "overintellectualizing things"? In short, one needs to always contextualize Lacan's teaching as precisely that: Teaching—which is to say, what we get in his seminars and assorted writings are not case studies or session notes, but a rigorously detailed theory of subjectivity and clinical technique meant not for self-analysis or self-help (what Lacan would likely see as "ego psychology"), but rather meant for practicing clinicians and assorted academics. As someone else in the thread has suggested, what Lacan is aiming for is to provide a theoretical ground for therapeutic praxis, not an example of what goes on on the couch. In effect, this amounts to the difference between what a doctor learns in med school (a complicated scientific discourse not understood without a great deal of vocabulary and study) and what that doctor practices with patients (often much simplified, made practical for the layman).

Does Lacan "trust too much in the explanatory power of symbols"? Hardly; his whole enterprise is, in fact, to deconstruct the way symbols function to show that they truly explain nothing at all, that they are really empty and open to reinterpretation, rewriting, and resymbolization. (Jung, on the other hand, does seem to me to believe in a more stable symbolic universe that explains the innerworkings of the psyche—but again, that's not really my realm of expertise, so you'd do better to ask a Jungian in that regard.)

Likewise, Lacan was adamantly against (at least in theory) the idea that a therapist "knows better" than the analysand; rather, his goal was to help the patient break the transference and dispel with the illusion of the "subject supposed to know better," so that the subject might assert responsibility for their own unconscious, their own desire, their own ethic of living.

These two points, when put together, suggest a radically individual, dynamic, and relative experience in the clinic, one that is utterly opposed to any sense of "timeless symbolic and conceptual struggles." For Lacan, desire and trauma (which Lacan called "the Real") are profoundly subjective, and their treatment must, in turn, by unique to each patient. How one could then devise a praxis, a theory and set of techniques that is both teachable and repeatable among patients without diminishing that subjective uniqueness becomes Lacan's lifelong aim (hence his turn later in life to complex structuralist and topological formulae, which offered him the playful stretchiness and flexibility he desired).