Many parts of the Drupal theme system tightly couple data and front-end design. Most of our template files are named for the data structures that feed them rather than the design components they produce. The templates know too much about their source data.

The future of front-end web development appears to be dominated by Web Components and Javascript frameworks; each with their own opinions about how data and design intersect. For Drupal to excel in that environment it will need more options for engaging with them than the present default approach to "headless" Drupal. Cutting out the theme layer entirely is not a viable option for Drupal core.

Panels module draws a clearer line between the components that handle source data (context plugins) and the components which handle front-end design (layout and style plugins). This presentation will make suggestions for how Drupal core can adopt concepts within Panels to be better prepared a future that expects cleaner decoupling.

Slides: http://palantirnet.github.io/slides-panels-web-components/