I think that Madame Armfeldt in the musical is sort of a vulgar woman, and Wheeler sets her up that way early on. One of her first lines is "Don't squeeze your bosoms against the chair, dear. It will stunt their growth." At no point is there much suggesting a refined gentility, although there are pretensions to that. There is a clearly Wildean phrasing to some of her lines, but even Lady Bracknell, a somewhat vulgar woman (despite being quite upper class), would not descend to some of the rather classless things that Madame A says. She speaks well (despite "bosoms" instead of "bosom" or "breasts"), but the sensibility behind her lines does not bespeak good breeding.
Re Stritch: Having said that, her "whoo!" was perhaps a bit much. I also thought she sentimentalized the character in some ways, as I think too many actresses have done. I had long wanted to see her in the role, but by the time she got to playing it, she was in her "Underneath this gruff exterior, I'm a lovable softie" phase.