As to what I think was your suggestion about the poem itself--that Shade is supposed to be second-to-Frost because VN sensed English verse was one of his lesser gifts--it's an intriguing idea.
That is what I was suggesting, but I'm sure I'm not the first to suggest it. I'm sorry that I don't remember where I've seen it.
Jansy Mello writes:
Jerry Friedman, quite
often in Pale Fire it is suggested that Gradus is Kinbote's
automaton, his clock-work toy, his (and our) death drive. You might remember that in
Nabokov's earlier novel, King, Queen, Knave, there are automatons, a
gardener trundling a barrow, a Red Vanessa...
I'd say that /Kinbote/ often suggests that Gradus is an automaton or clockwork toy, and associates him with death (especially) in the last line.
I must admit I haven't read /King, Queen, Knave/. Those similarities are interesting (though the Vanessa is hardly surprising).
Jerry Friedman