Theme developers for WordPress would be glad to learn that the forthcoming 4.1 release on the 10th of December will take off the custom background and header screens from the admin section. The screens will instead be swapped for deep-links within the customizer. Basically, the menu for header and background would still appear in the admin section but modifications would be deep-linked to the WP customizer.
This comes as a good news for theme developers on WP as they will not have to style background screens and custom header. The important aspect to take into consideration though is whether the hidden pages would cause any issues for updating users. This update comes as a crucial one as new users tend to expect to find the separate headers page in the customizer.
During WordPress 3.4 update, the header upload was taken out of the customizer because of issues arising from images cropping. For the previous two year,the extra admin pages turned out to be confusing for users. Some theme controls were available in the customizer while others were in the admin section which proved to be inconsistent and divided between frontend and backend.
The changes that would come with 4.1 would show the custom background/header option with deep-links to the customizer for the front-end. The widget screen as well will show a link to the customizer widgets section. WordPress’ ultimate plan is to streamline everything to the customizer and to remove the admin links. This would surely make things easier and more accessible for developers.