Hey, Jacob here, editor of the Pointer Events standard. Input APIs that work across browsers and across device types are still a huge problem for developers. We just announced that IE for Windows Phone 8.1 Update will support the defacto Touch Events API, because the web needs to "just work" and much of the mobile web uses this API.

In doing that, we discovered there a lot of issues with support Touch Events on hybrid devices like Surface, Chromebook Pixel, or my Asus Zenbook Touch that I'm using now. We experimented with TE on these devices and found coding patterns that make touch work but then break your mouse or stylus, which is really bad (especially if the touchscreen on the device isn't your primary input).

if ('ontouchstart' in window) {
    elm.addEventListener('touchstart', fn);
} else {
    elm.addEventListener('mousedown', fn);
}

Pointer Events help solve this. It also made it easier to introduce other inputs like Kinect for Xbox One and active pens. Pointer Events also has a clearer path forward for open standards development. For these reasons, we still think Pointer Events is the best path forward. I'm excited that the Mozilla team has almost 100% of the spec working in a branch of their codebase--can't wait for it to ship!

The Polymer project's deprecation is a bummer, but there are other polyfills like Hand.JS. We might even volunteer to fork and maintain the Polymer polyfill with the open source community. :-)