Hi Custer,
Thanks for the news, I am looking forward to it!
My recommendation is to bring blocks of content into the order of their priority in the code itself. That's advantageous for users with small screens, for SEO and for the success of people using WPB. The style sheets should take care of presenting the content on the appropriate device. In other words, the priority of content influences the order in the code as well as the styling.
A challenge could be how to determine the priority of content blocks for making them appear in the right order. A no-brainer is the two column layout with the main navigation on the left, the main content in the middle: Priority: 1-2 (left - right column). Or if the main navigation is in the right column: Prioritiy: 2-1. The navigation is more important than the main content. But what about e.g. a two column layout with the main navigation across on top: Should it be 1-2-3 or rather 1-3-2 (top - left - right)? Would it make sense if the priorities could be assigned as an option in the WPB user interface?