"The Pit" has a reputation as one of the worst novels in the New Adventures series. I have not read enough of them to make that assessment, but I can say it is a proper mess of a novel. I think this mess happens because Penswick has a concept, but not a plot. The concept is basically Doctor Who inside the book of Revelation. The question, then, for Penswick is how he is going to get the major elements of that story into this one. Penswick tries to create a sprawling epic of a novel, with action in three major locations focused primarily on three characters - The Doctor, Bernice, and the enigmatic Kopyion. To add mystery and misdirection to the story, Penswick relates the events of these three characters and locations primarily through side characters, though Bernice gets more internal monologue than the other two primary characters. Thus, we see The Doctor's part primarily through the famous poet William Blake's perspective, Kopyion's part primarily through his underling Carlson's perspective, and Bernice's part primarily through the android soldier Spike's perspective. There are numerous other side characters necessary to keep the contraption running, and parts of the story get told from their perspective, but once they have served that function, Penswick then kills them off in particularly nasty ways, except for Blake whom he cannot kill off but probably really wanted to.
The problem here is that the events on the three locations do not logically relate. This is particularly true of events on the planet Nicaea. Society is breaking down into total anarchy, yet what has this anarchy to do with events on the Planet Without a Name or with The Doctor wandering through holes in reality to alternate universes (or are they? another thing Penswick never bothers to make clear). The Doctor and Bernice never go to Nicaea, so what is all that action, nearly half of the novel, doing here?
One could go on about all the things in this book that just do not make sense. For instance, the androids are thoroughly inconsistent in concept. Are they "metal men" (walking toasters as Benny describes them) or organic simulations of humans? Both, but only when needed to be. And what about the Nicaean religion? All this stuff about the Prime Mover (God) and the Form Manipulator (Satan) suggests some kind of technological origin of Nicaean society, and that Nicaean society was created to fulfill some machine's or organization's purpose. Yet, that avenue is never explored, nor is it fit into the resolution. Why is half of The Planet with No Name artificially created by the company that makes the androids? On and on it goes.
Then, one gets to Penswick's conception of The Doctor. Here, The Doctor is utterly useless. He spends most the novel completely lost, making snide and cryptic comments to Blake, showing none of his usual compassion and good humor, and has no part in the Deus ex Machina ending of the novel.
Blake is also useless and unnecessary. William Blake is here used not as a guide for The Doctor, as Vergil was for Dante, but as a commentator to point to the correct thematic interpretation of the action for the reader. Fulfilling this function means that no more thought went into the character of Blake or why from the standpoint of realistic action rather than thematic convenience, it is William Blake of all the humans throughout history who ends up in the pit. Penswick's Blake is an anachronism, who does not think or talk in early 19th-century ways, but in 20th-century clichés.
To summarize, "The Pit" has many interesting ideas, all of which go nowhere. There is not much of a plot; instead, the "story" is mostly a situation. The story has more loose ends than a rope ladder cut in half lengthwise. The Doctor Who elements are almost completely unrecognizable. The story is disturbingly violent and grim from beginning to end.