From other posts I understand that tables may not be directly supported in the cascade story map template, but I would like to vote for some manner of incorporating them directly. For a workaround, I will be using an image of an HTML table, but lose responsiveness and styling capabilities with this approach.
An example of the current limitation is below showing a small table with a header and two rows with data. The table is on a html page and inserted via an iframe so we can style the contents.
The highlighted blue area is extra space in the div with block-media class applied. For content whose height is smaller than the minimum height of this class, empty space is left and I don't see a straightforward way to remove it.