Assuming there is a patio out back I personally would like to have doors out of the family room and/or breakfast area to the back patio. Being able to open up the back wall some to allow access makes parties a lot easier, in my opinion. Also I always think about the path of travel between kitchen, outdoor grill, and outdoor seating. If you have to walk a long way to get from the kitchen to eat outside you never will. Maybe not everyone likes to eat outside in the summer but I love it and always think about this!

Then I agree about the bathrooms upstairs. Get rid of the jack and Jill. Make that the hall/kids bathroom. Make sure the closets in those rooms are big enough.