I'll try to add a thought without referring to a specific tradition.
Korach lacked refinement of character but how was any of the men Ruach Hakodesh ever revealed something without flaw? Moshe was not and he knew, which seems contributed to him being the most humble man on earth and particularly inclined to listen to G-d and follow suit. However Moshe killed an Egyptian overseer in a rage of fury. G-d still called Moshe to service in the desert. Years later Moshe disobeyed G-d by striking the rock in a rage of fury (same hidden flaw of character surfacing again) and in the aftermath Moshe was not allowed to enter Israel, still G-d did not stop using Moshe as leader of Yisrael while he lived.
Put very simply, I conclude from this that the prerequisite for G-d to approach a man and convey something to him is not perfection in the man (that's not ever been seen happening) but G-d deciding to do so. If G-d never covered the hidden sins before His face, as David prayed (well aware that properly, who may stand before G-d in a sacred place? He who is completely pure - that's no man), then there would be no G-d approaching a human, as things have come to stand, at all.
As a side note: No offense meant but "level" and "conductive" in this context both seem to sound indicative of inclinations to schools of thought that sound esoteric to me. I seem to find in the Torah that Ruach Hakodesh is not into esoterics but very opposed to any system of it.