For example, it would be great to be able to add the contact form to the contact page section with social media icons, or have the option to include a text box or image into a section & adjust layout. A build-your-own layout section?
If that option isn't possible (or would start looking too much like Wix & other layout building sites), perhaps being able to reduce the width of a section to place two sections beside each other would suffice - some items like the social feed and contact form don't need to take up an entire section. Even just an auto-scaling "full-width", "half-width" or "1/3rd width" button would work for desktop & tablet sites, and on mobile devices it would just place the left to right sections in a top to bottom order.
