I really enjoyed these brownies. The lemon flavor is nice but not overpowering. I had no issues with the frosting and think you may want to add more lemon juice if you want a stronger flavor.
Brownie part is amazing but the icing is absolutely horrible. I'm not sure if it was adding the lemon juice to the cream cheese or what but it smells and tastes so bad. I would make the brownie part and then top with a lemon glaze instead.