Some ideas that would bring people back:
* Wildly new, terse, and clear syntax and a great library of built-in tools that are briefly and intuitively named.
* Easily write and design interfaces that generate both/either back-end or matching integrated front-end code which is off in its own directory and can easily be used by existing JavaScript and HTML.
* Similarly be able to generate the JavaScript front-end code that use those JS client libraries with easily writable/pluggable generators so that it can generate Angular 1.x, 2, ReactJS, Bootstrap, etc. in "best-practice" ways that can be updated frequently as the community changes.
* Simultaneously provide the option to serve very similar pages using straight HTML, degrading even to the point that a text only browser could use the site easily.
* Easily define responsiveness of pages.
* Support multiple 3D, 4D, etc. interfaces with customizable inputs to be forward-compatible without overdoing complexity (i.e. it's really pluggable).
* Similarly support generation of almost any kind of service integration, with easy pluggable authN/R.
* Easily scalable.
* Relational, noSQL, versioning DB (noms) support.
* Make fun books for kids and a site where they can share what they've written, write games, build things, etc.
* Make it integrate with every browser, even some older versions, operating systems.
* Make it compile low-level vs. byte code so it's fast as shit.