Styles Option on New Document Settings.
I see far too many younger designers not know how to use or simply refuse to use paragraph styles, character styles, layers, and even master pages.
I'd love to see these options available in the open new document settings, just as we pick the page size, margins and gutters, I'd like styles to be an option.
As a frequent contract designer, there's nothing worse than going into someone else's InDesign document and spending more time organizing the file, making sure the entire document is formatted properly with the correct styles, separating items in proper layers... Anything to help new documents focus on making sure the file is going to be consistent in its typography.