This should do it I think.
/Categories - [All Categories Page]
Without having to install an additional plugin and creating a custom page to list all Categories with the use of a Widget, I believe it would be nice to be able to travel to something like "examplesite.com/categories" to get a nice listing of categories. Similar to the way that Topics are listed in categories. Any thoughts?
You mean like the homepage? Or just all topics from all categories?
A listing of the homepage similar to how topics are displayed in individual categories.
Next theme may have a more classic homepage as well.