I agree with the top end of your list, for the most part. But why people continue to revere Thornton Wilder as a playwright completely befuddles me. His dramaturgy is flawed, his sense of rounded characterisation the dramatic equivalent of tone deaf; he didn't even write that many plays. He is basically a novelist, his use of the narrator akin to the omniscient voice in fiction. His two plays, mentioned here, focus on highlights, they do not feature neatly-structured scenes. Tennessee Williams commented that Wilder had never had a conjugal relationship, and I think this is reflected in his rather bloodless portrayal of family life. This is equally apparent in his screenplay for Shadow of a Doubt.
On the other hand, the inclusion of Buried Child is delightful. Sticks and Bones might substitute for Topdog/Underdog; but the list puts the classics in the right order, I think. Well, no, I think Cat on a Hot Tin Roof is more substantial in every way than is The Glass Menagerie.