One of my favorite WordPress releases is 3.5, when Daryl Koopersmith banged out umpteen lines of JS to gives us the new Media experience. It was a game-changer for the admin interface experience, and will echo in WP eternity. A utilitarian fill-out-form-and-submit-page will (probably) never go away. But JavaScript (with an MV* framework) is key to building user interfaces to deal with complex data in user friendly ways. Let’s go there.