We use the Revised Common Lectionary, which you'll find is suitably free of gnostic or so-called gnostic texts.
It's also free of a lot of scriptural verses that make people uncomfortable... sorry, just had to make a jab.
But yeah, accusations of "Gnosticism" are typically overblown.
I can see how that can be a horribly misused word. I was surprised to see it was used at all in modern day western parlance. There are legitimate unbroken expressions of it in the East (Yazidi for example)...the West it becomes a little harder to trace and look at in modern times. Even if people want to call themselves gnostics, it is usually too technical and philosophical/New Age-y to be taken as anything as 100% Authentic. The biggest fear is for it to turn into a trendy philosophical/trendy word that can be used as a generic "catch all" word.
I think Gnosticism in the West pretty much dovetailed with hermeticism and neoplatonism and all the weird variants thereof into a catch-all "Western esoterism", finding expression in alchemy, astrology, and other disciplines like that, through the rosicrucians, masons, etc. and today in parts of the New Age movement. Talking about "authentic" Gnosticism seems dubious because it was never a stable, unified school of thought.
Now on this, I think you raise a very excellent point which touches close to the core of my argument. You argue that Western Gnosticism was coterminous with the occult; I concur; I would argue this conditon existed in the East as well, althoigh frankly there is so much mysticism and dissimulation in non-Christian religions of the East that this fact seems to "shrink to insignificance." We should not forget at any time however that according to St. Irenaeus of Lyons, St. Epiphanius of Salamis and other credible Patristic experts, the Protoheresiarch of Gnostic Christianity was the dreaded Simon Magus, wno was as much of an occult figure as anyone else, in purely Eastern terms.
The Roman Marcus, who founded the sect of the Marcosians, was a almost a satire of Simon Magus, resorting to what amounted to parlor magic in order to swindle Old Ladies.
However, my point is that in being coterminous with the Occult, Gnosticism managed to essentially adopt the most sincere expression of Theistic Satanism ever attained. The Ophite conceit glamorizes the Serpent and makes God out to be the devil. Yazidism glamorizes the Peacock Angel, a rebellious archangel, whose origins closely parallel those of Satan or Lucifer in Christian thought, who is more specifically based on the Islamic Shaitan. My view is that only Gnosticism represents a sincere, earnest worship of the devil on the basis of the error that the Old Testament deity is somehow malign, which is an adolescent theology, ideal for those caught inextricably in the torments of Teen angst, but otherwise grossly erroneous.