For this salad, you want to use a softer lettuce such as a butter lettuce or green or red leaf. It works better with the blueberries, as something crunchier, like romaine, might overwhelm the berries texture and flavor. The dressing uses basil as the herb, but you could try mint instead. A little arugula would work well, but go lightly or the sharpness could drown out the other ingredients.