I was re-reading this post at "A Paladin in citadel" blog, and i was particularly struck by some comments below which compared it- in a certain sense- to the gonzo-style of Arduin.
I think that your premise may be flawed: I'm pretty sure I remember Hargrave mostly being mocked or derided by gamers of old. Granted, pre internet, I had much less opportunity to hear lots of opinions, but there didn't seem to be too much love for arduin across several areas I lived and gamed in.
I've read World of Synnibarr. I love the Arduin books, but there are very few essential differences between them and Synnibarr. McCracken had the misfortune of publishing in the wrong decade to benefit from the nostalgic "respect renaissance"
But, in a last comment we read:
Arduin may have been "gonzo" (though at its heart it was really just hobbits and dungeons), Synnibar was... plain mad. Besides, Arduin's "gonzo" had more to do with setting flavor, whereas Synnibar's crazy is built right into the "rules". :)
So i honestly don't know, since i never played it, and this is an exceptional post on my blog because i am not intentioned to deal with these kind of games, (this blog is about fantasy rpg's), nonetheless i think everyone should judge for themselves.