Setsuna has such presence that you completely forget that she's itty. She and Shioriko would be great as a couple — their game story is pretty rich.
(Also, in one of Shioriko's bond episodes, she's having trouble figuring out her themes and musical styles as a new school idol, and the other girls are offering suggestions, like mixtapes that remind them of her; Setsuna — completely guilelessly — gives her a copy of the Imperial March and says Shioriko reminds her of Darth Vader, and you can tell she means it in a good way, but....)