1) I really don't see how that would compromise structural integrity at all.
2) There should be a return law in your state that would allow for you to return the car within 2 to 4 weeks of purchase with little money lost.
3) Asking for a replacement car is entirely acceptable.
4) This issue is clearly not damage. It's a defect. The panel was e-coated that way. That's shocking to me because I've seen auto bodies built in person and usually if the machine welding the panels together senses the most minor of problems, the issue is flagged or the process halted. That is a major defect. If the machine didn't catch it, then how in the world did it get past a QC inspection?
I think Toyota/Subaru has a manufacturing problem on their hands because I've read about BRZ/FRSs being delivered with body panel fitment problems.