Overall, the cascade story map mode is very aesthetically pleasing. The smooth scrolling functionality makes it more of a story then just a powerpoint or a map. Being that it is a Beta and not fully functional, I assume there is already alot in the works for the next version and that some of the constructive criticisms I am about to mention are already being considered.
There need to be more text options all around, but more so for the title texts. As you can for the non-title texts, you should be able to change color, alignment, and bold/italic/underline. For the text all around you should be able to change size and font. I could inspect the element and edit the html for non-title text and font changes would stick unless the text was moved, but for the titles font change wouldn't stick at all. The four text styles for titles and non-titles (black with white halo, black with white box, white with black halo, and white with black box) aren't enough for a conducive and dynamic story map.
There should be more video options for the story. Due to certain privacy issues the videos we would like to use aren't posted online anywhere and therefore we couldn't use them. Our work around was converting them into gifs and cutting them to a fraction of their length in order to fit the max gif file size.
We noticed that views and extents change as the user switches between devices. Although you can see the multi-device preview when adjusting graphic location, it doesn't entirely show how it will appear once published. For instance, the title segments which only show a cross section of the graphic on the computer show the entire graphic on a mobile device. This is misleading, when a user is under the impression they are showing only a portion of a photo for specific reasons (not showing someones face is an example).
Across the board there needs to be more customization. The few choices for placement, size, and theme are limiting. If the same customization options as the prior story map options were present in this it would be ideal. Hopefully these critiques are helpful moving forward with the final cascade product.