There has been a lot of backlash from the WordPress community recently over the theme review team’s decision to require theme options to be implemented in the Customizer. But this decision really is in everyone’s best interest.
WordPress 4.2 shipped with the ability to switch themes in the Customizer. When theme-installation is incorporated in a future release, the entire theme selection and customization process will be streamlined to a seamless workflow in which the user never enters the WordPress admin. This functionality is specifically targeted to users that leverage free WordPress.org themes, so it just makes sense for all themes hosted there to be Customizer-optimized. But the real win is the ability to live-preview changes before publishing them. With the Customizer, users know exactly what their site will look like when they publish their changes, a critical feature for anyone who cares what their site looks like when it’s publicly available.
Many people have been critical of the user-oriented nature of the Customizer. But its power is much stronger than most realize; one of my favorite use-cases for the customizer is custom CSS. This is the easiest way for users who want to go further to get into coding and offers a seamless experience that is infinitely better than the easy-to-kill-your-site-or-lose-your-changes-with code editor in the admin. In fact, I’d love to see a customizer-based custom CSS functionality in core as a replacement for the code editor, although I have a feeling that proposal may be too political to advance to an implementation. Bottom line, the customizer lowers the barrier to entry into WordPress development, contrary to many people’s thinking.
Yes, free themes requiring use of the Customizer will lead to a similar movement for client themes and premium themes. And that’s okay. In fact, by having everyone using the same underlying framework, users know where to look for options and have the confidence that live previewing provides. And WordPress will provide a more consistent visual experience for users as well.
You can really build any functionality into the Customizer. Theme-switching, widgets, and menus were all built as plugins first and continue to use the publicly available customizer API to run. So if you must, you can still create ridiculously complicated UI elements that no one will be able to figure out how to use, but you really don’t need to.
And complaints about the amount of screen real estate available and the 300px default width show a lack of creativity and resistance for the sake of resistance to change. Start by removing all of the ads, external links, unnecessary branding, unnecessary options, and general clutter. Make your options self-explanatory – if you need a paragraph to describe what it does, it probably shouldn’t be a user-facing option. Do you still have so much UI that the experience is completely unusable? Try an outside-the-box solution, like utilizing the core media modal (header images and core media controls use it), a custom modal (theme details modal in core), or a slide-out panel (widgets in core and eventually menus in core as well).
No, the customizer isn’t perfect. But it’s time to give it the respect it deserves as a significant part of WordPress. After three years of slow adoption, the theme review team’s decision to enforce its use is a welcome sign for users and a positive decision for the WordPress community as a whole. I’m excited to see what developers do with the Customizer’s amazingly powerful API and what core contributors come up with to improve its design and usability.