Vindication! For Mark Bittman's vegetable soup guide. Well, for one of the soups. I went back and tried the "vegetable broth," and it came out well. The mushrooms and tomato must be the key factors. (Note my previous dissatisfaction.) I will say, though, that the flavor was most adequate when it was cool. Once warmed up, it was weaker. I've actually read that food's flavor is strongest at room temperature, but can't remember where. Hmm.
Anyway, Bittman presents the soup as going with a piece of toasted good bread, but that clearly won't do for dinner for me at least. So after making the broth, I used some of it to make a simple dumpling soup. The dumplings I'd made before and frozen. Other than those, after straining the broth, I just threw in some ginger, scallions, and lettuce. Napa cabbage or plain-ol'-cabbage probably would have been better for flavor, but I had lettuce on hand.
First boil the dumplings separately, unless you don't mind the broth being cloudy. In the background are the vegetables after removal from the broth.
Simmering broth with ginger and scallions, and just cooking the lettuce.
Pour soup over dumplings et voilà!