Off the bat, there is a ton of value in the Experience Builder. It looks at the whole picture and incorporates the data, the story behind the data, and all of the related information into a single view. Great job! A few of my impressions and questions are below:
1. Auto-expanding sections
Currently, if you add text, that box has a set height and does not expand automatically if the screen width is compressed. Ideally when switching to a mobile view, it would be nice to not have sub-scroll bars.
I think I saw that you can toggle to Mobile View then select Custom Content Width and resize there for mobile view. Is that the ideal workflow?

2. Adding dynamic legends
It would be nice to add a legend below the map, much like this other product. Ideally, the legend text could be created dynamically. Am I missing where the legend option is? Or is that a later release?
3. Adding tables
Will it be possible to add tables as a text object?
4. Widget options cut off
When resizing the builder window, some of the widget options get cut off without the ability to scroll.

5. Scrolling in mobile live preview mode
Again it's possible I'm missing something, but I can't scroll when in Mobile Live mode.