Yes, exactly. I suspect that I could teach a full-semester secular class on the literary impact of the Gospel of Matthew alone, and between several rounds of "spot the Christ allegory" and "spot the different types and elements of the Christ figure" (Is Dirty Harry a Christ figure? What the hell happened to "love thine enemies"?) and "what has this parable turned into in the modern world" (Oh, that's why my insurance company is called "Good Samaritan") I'd have a full schedule. And no one would have realistic grounds for complaints.
Job is another good one. And Genesis -- oh, we can do creation myths and questions of reification for months.
Frankly, from a literary point of view, there's almost nothing in Isaiah. I't's not even good prophesy. Of course, from a theological point of view, it's critical.
And that's the difference. The material per se is not objectionable, but it's all in what (and how) you choose to treat.
