Harker isn't an oddball at all. He is very bright.

"This isn’t helped by the fact that, where Harker felt justified in lumping together Percy, Scott, Child, Sharp and Williams (whose methods and aims were very different)"

As I said, Harker is very bright, and I feel that it misrepresents the whole book to describe what it attempts and what it does as simply 'lumping together' the people named above. One the contrary, the book sets out to set each person in his context.