To customize how posts of different post formats appear in a Query Loop, I think what's needed is some sort of "If-statement" block that will render its contents if (and only if) a certain condition is met - e.g. the current post matches a specific post format. You could then use several of these "if" blocks to create different templates nested in the same Query Loop. The UI might be a bit tricky to balance between editor-friendly and WYSIWYG, but I'm sure the devs and designers could find a solution, given enough time.