Cook the pasta according to package instructions until al dente. Drain and set aside to cool.

Preheat the grill to medium-high heat. In a large bowl, combine the zucchini, yellow squash, red bell pepper, eggplant, and cherry tomatoes. Drizzle with 2 tablespoons of olive oil, then sprinkle with oregano, garlic powder, salt, and pepper. Toss to coat.

Place the vegetables on the grill and cook for about 5-7 minutes, turning occasionally, until they are tender and have grill marks. Remove from the grill and let cool slightly.

In a large mixing bowl, combine the cooled pasta and grilled vegetables. Drizzle with the remaining tablespoon of olive oil and toss to combine.

Add the chopped basil and feta cheese (if using) to the pasta salad. Toss gently to mix everything together.

Serve immediately or refrigerate for at least 30 minutes to allow the flavors to meld. Drizzle with balsamic glaze before serving if desired.