Add all green goddess ingredients to a food processor and blend until smooth. Cover and refrigerate while you make the rest of the salad.
Turn on grill super high - 550 degrees. Brush grates with a little olive oil. Cut 1 head of romaine in half, lengthwise. Brush the grilled side with olive oil and place onto hot grill to get some char. it should take no more than 2 minutes to get there. Remove from heat and set aside to cool. Cut the rest of the romaine heads into pieces and place into a large bowl. Set aside.
Brush corn with olive oil and sprinkle with salt and pepper. Grill for 8 minutes. In the meantime, prep the shrimp. Place raw shrimp into medium bowl. Add 1½ teaspoon salt and ½ teaspoon ground black pepper and 2 tablespoons olive oil. Toss together. Place shrimp onto hot grill grates to cook for 2 minutes. Flip and cook for 1 more minute. Remove shrimp and set aside to cool. Remove corn. Turn off grill.
Cut corn off the cobb and toss into salad. Split the salad among 4 large plates. Top each with shrimp. Cut grilled romaine halves into half again to give you 4 pieces. Place one grilled piece onto each plate. Cut avocado and place some on each plate. Split grilled shrimp among each plate. Drizzle each salad with the green goddess dressing.