I’m concerned that WordPress has been caught flat-footed while the world races ahead. MCE buttons, shortcodes, and even the customizer are way behind what others are doing. The post/page editor is one of the most critical part of WordPress. It is the face that WP presents to those publishing with WP on a daily basis. These are the people who ultimately decide if WP is the right solution to meet their needs. It is a serious problem that this part of WP is so primitive. To see what is happening in other places there are good examples to be found in the various “Builder” utilities used to create HTML emails. Virtually every ESP provides its users with such a front end and most are quite powerful. To see an example I suggest you build a page with with this open source project... https://beefree.io