“Country-Style” carries multiple definitions and connotations. The author of 9-45: Country-Style Sausage Medley surmised that a dish containing this many varieties of vegetables must be “country-style”. Chicken sausage is a low calorie option, however, it lacks the punch of flavor a good beef sausage can provide.
This dish contains a lot of vegetables already. If I had to add any other vegetables, I might substitute the cabbage for Brussels sprouts.