If I had to guess, I’d imagine some sort of “reader mode” is coming to the Watch: in other words, when you open a link on your Watch, this minified version of WebKit wouldn’t act like a full browser. Instead of rendering all your scripts, styles, and layout, mini-WebKit would present a stripped-down version of your web page. If that’s the case, then Jen Simmons’s suggestion is spot-on: it just got a lot more important to design from a sensible, small screen-friendly document structure built atop semantic HTML.
But who knows! I could be wrong! Maybe it’s a more capable browser than I’m assuming, and we’ll start talking about best practices for layout, typography, and design on watches.
I had this inkling for a long while that there wouldn’t ever be a browser in the Watch due to its constraints, but instead I hoped that there might be a surge of methods to read web content aloud via some sort of voice interface. "Siri, read me the latest post from James’ blog," is probably nightmare fuel for most people but I was sort of holding out for devices like this to access the web via audio.
Another interesting aside is that both Safari OSX and iOS have had a reader mode for a long time now, but have it as an option enabled by the user while viewing the content. Bypassing the user-enabled option would be the difference on watchOS and where our structured, semantic chops are put to task.