Our team is using a homemade time planning tool. In the past it used to be an excel, these days it‘s an app. Each member had two rows (morning/afternoon). Each column is a date. The team filled it out using background colors. Each color represented a category like holidays, ill, onsite etc. One easily gets an overview of the whole team while providing all the details. At some point you run out of colors since the shades are too similar. We added custom patterns with mixed colors for each category.
In text editors we are stuck at text, these days with a few colors. There are barely any shades of color, no background colors or even patterns at all. The maximum is usually a TODO: which gets a yellow background. It think there is still a lot of colors, patterns and shades to explore to create more of an information dense image than a book. Animation is yet another beast.
Another thing missing in todays editors are logical connections. We define methods, but there is no visual hint where they are called from. Files are still displayed as trees instead of networks. Clearly defined interfaces would show up unless we have the classic spaghetti code.