About the concept of "design": Before anything else, it entails intent. Those who think the elegance, sophistication, grandeur, or whatever of the physical world is evidence of "design" are implicitly claiming to know something about the intent of the designer of the physical world. But how do we know if our universe is any of these things if we have nothing to compare it to or measure it against, including the express intention of its designer? There is a possibility that the physical world was "designed", but not very well. For all we know its execution fell short of its conception; or, that it's a poor specimen, compared with the work of other cosmic designers. This is part of what Stagger Lee was getting at when he said the we can only understand and evaluate design in relation to known instances of design. I would add that we can also evaluate design in relation to the intention of the designer. If I make something really useful or beautiful by sheer accident, or while attempting to do something else entirely, I can't be called the "designer" of that useful thing.
People who claim the physical world must have been "designed" by a divine intelligence are really just expressing their own sense of awe (which others may or may not share, depending on their sensibility), unless they can tell us something about the intention or goals of its alleged designer, or compare it to a less inspiring instance of cosmic creation. They would, in other words, have to either know the mind of the creator, or know about the work of other creators. Anything else is pure tautology (like simply defining the designer of the physical world as perfect, and its creations as, by definition, perfect). But even then they would also have to explain the bits of the physical world that seem simply nasty, like the Ebola virus. And virologists have described this Philo virus as darkly elegant under the microscope. The rest of us are left to marvel at its brilliance as a means of mass death-- if, that is, its designer intended it for that purpose (and perhaps it was just a mistake...) In any case, if the stars and the ebola virus were designed by the same agent, with the intent of, respectively, awing and killing us, then IT was a good designer, but a morally incomprehensible one. You'd go crazy trying to figure it out, let alone worship it.