I had not read any Stevens until I read the article you posted, Nick. One of the things I love about the New Criterion is that I always get to read about some decent writers I haven't heard of or I have only a mere recognition. It helps me expand my literary education which would otherwise tend to stagnate because of my laziness.
I briefly perused some Stevens and tried to find the poems mentioned in the article. I can see in the few poems I read how both you and the author came to your conclusions. There was a lot of nonsense in the poems I read. I also enjoyed the line you quoted from the article. The New Criterion finds some decent critics and writers. I especially like Terry Teachout. From Wallace, I did enjoy The Man Whose Pharynx Was Bad and The Snow Man. Especially The Man Whose Pharynx Was Bad. I thought this a very nice stanza:
The time of year has grown indifferent.
Mildew of summer and the deepening snow
Are both alike in the routine i know.
I am too dumbly in my being pent.
Whitman I might revisit some day, but I remember having to wade through quite a bit of sillyness there as well to find anything I liked. It makes me wonder what a writer does with his bad or lesser material. I'd be inclined to toss it or at least not publish it, but I suppose it must be shared for the sake of improving yourself through someone else's criticism. Of couse some writers may not think they have lesser material. When I write I'm inclined to think the opposite and am loath to share.