Well Mr Onyx. The question you have laid out is very rhetorical. As, any sandwich can be perfect, whilst any sandwich can be aghast. The properties of the sandwich come down to the creator of the sandwich. What are there expertise in the culinary world? What tools are available to the creator to construct such a delicacy? Etc.
But, as a master of the craft and official head sandwich maker of Halo RP (and should be Revival) the answer to your question is a ham, mozzarella, and sauce blend of minced onion, Dijon mustard, melted butter, and a hint of Worcestershire sauce on a sweet Hawaiian roll cooked in the oven for 15 minutes at 350 degrees.