I agree with other posters that a few extra seasonings really take this recipe up a notch. The creamy sauce is delicious, and you're flexible to sub whatever veggies you have on hand.
Like other posters, used black olives instead of kalamata, and added a bit of feta cheese, crushed red pepper, and oregano. Left out the tomatoes (can't stand 'em!), and served with Ellie Krieger's recipe for zucchini crisps on the side. Used a little more pasta than called for, but did not change the amounts called for in the sauce (yougurt, mayo, etc.) and it was still deliciously creamy. Made enough for 5 servings, so it's perfect for a light dinner with lunch for the next day!