Leaving a vertical space between paragraphs is the US convention (see Wikipedia), which is going to be familiar to most people nowadays due to the default browser stylesheet and various markup languages. You can change that on your own creator profile and game pages if you ask for custom CSS, but in the various editing areas I'm guessing it could be tricky, since Enter for paragraphs and Shift-Enter for hard line breaks is a near-universal convention nowadays, in apps ranging from chat clients to office software. Some of them don't leave a vertical space, but they still make the distinction between a paragraph break and a hard newline.