Phil asked (below) about the deal-breaking potential of 2% milk v. cream. It's true that there are some recipes (esp. baking) where I would not make that substitution. And there have probably (and will be again) times when I'd categorically refuse. In this case, I believe the recipe said "milk or cream" so the fact that we had milk meant one less thing I had to buy. And also indicated that they felt the recipe would work with varying degrees of dairy fattiness. Whole milk has around 4% fat and I've found that, in many instances, I can switch freely between 2%, whole milk, or half & half without seriously compromising the recipe. (otoh, I'd only use 1% or skim to substitute for water; they just don't have enough fat to adequately stand in for milk, let alone anything heavier)
But thinking some more about this particular batch of soup, I think the reduced creaminess may have been one of the problems. I added, as per instructions, some Greek yogurt when serving. Mixing that in added some fullness to the flavor that had been missing.