Not I big fan of dill and mint, though I like the idea of using Greek yogurt and adding olives to the salad. What other herbs can you suggest?

Parsley and chives would be my next pick. But I also love Nancy's idea of swapping in a bitter green—I bet baby arugula would be really nice.

Another way to go would be to use some strong/bitter greens as an herb (for example, watercress), small amount of onion (spring onion, scallion or shallot), or trimmings from some aromatic vegetables (fennel fronds).

You could also use summer savory, chervil, chives, basil, and thyme. Just about any combo of fresh or dried herbs would work with this salad. If you can find it, a French blend called Fines Herbes is nice for salads and it contains a blend of most of the herbs both HalfPint and I listed. You can also use tarragon, but go easy on that because it's got a strong piney flavor that can take over and obliterate other flavors.

I would do parsley, oregano, and/ or marjoram.