Whisk vinegar, lemon juice, and honey in a small bowl. Gradually whisk in oil. Season vinaigrette with salt and pepper. (Can be made 2 days ahead. Cover and chill.)
Bring broth to boil in a large heavy saucepan. Stir in orzo, reduce heat to medium, cover partially, and boil until tender but still firm to bite, stirring occasionally. Drain. Transfer to a large wide bowl, tossing frequently until cool.
Mix tomatoes, feta, basil, and green onions into orzo. Add vinaigrette; toss to coat. Season with salt and pepper. (Can be made 2 hours ahead. Let stand at room temperature.) Add pine nuts if desired; toss. Serve at room temperature.