It would be great to have the ability to place one layout as an element on another layout. Where printing will repeat a Header Part, it's useless in Form mode. It would be great if the Header Part could come from a different layout or if a new Part such as a Layout Part could be defined that would utilize a different layout.
Even if the ability to nest one layout within another were limited to a horizontal area, it would be a big time saver.
If there were such a Layout Part, it would also be helpful for printing. A developer could merge multiple tables into one print job without having to resport to PDFs.