Is there any chance that the taste of the soup is supposed to be subtle? I don't "do" subtle!
Maybe you don't like subtle either.
I like our Princess's idea of sauteing some of the leeks. Maybe in bacon drippings. Save the bacon crumbles to use on top the soup with the crispy leeks and a touch of grated cheddar cheese.
If this soup was supposed to be "healthy" I think I just ruined that plan.