Well, even though I mostly disagree with his thesis, I still thought he was funny. Calling Donaldson's work "so flatulent that you have to be careful not to squeeze it in a public place" makes me giggle.
And yeah, I think that he's criticizing standard SF with the wrong tools, sort of like a classical music critic blasting Nirvana for overreliance on a single melody without sophisticated development. Other critics of SF focus more on the mythological feel of SF, and they get things righter. After all, some of the better-known Plot Devices out there include the golden fleece, the holy grail, Excalibur, and ambrosia and nectar.
If I criticize a Charles Dickens novel for its lack of mythological resonance, I'd get laughed off the block. So should this guy be.
That said, though, I still think he's a hoot to read. And gettin past his silly condemnations of plot devices, he's got some useful tips for campaign structuring. I like how he divides plot devices into three categories:
1) Coupons to collect (get all of these, and save the world!)
2) Vouchers to redeem (get out of jail free!)
3) Deus ex machina (step into the campaign in disguise and get things moving!)
These can be useful tools for a DM, as long as they're used subtly and judiciously. And though I laugh at this guy's essay, and use his advice, I won't invite him to my game

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Daniel