I've read some translations of some of the Gnostic gospels, and gotten an overview of Gnostic Theology. The theology suffers from the same problems as Platonic cycles and epicycles--since they insisted on sticking with their base premise even when it is a bad fit, and trying to modify it to fit instead of questioning their base logic, it got so convoluted and self-contradictory as to become completely absurd. To top it off, because Gnosticism was a very esoteric, secret religion where the whole point was that the upper ranks, the 'illuminati' if you will, had 'special' knowledge that lay people didn't, everything is covered under symbols and metaphors, or explained as such.

As a result, the Gnostic gospels read like someone was smoking something really good when they wrote it.