It would appear that Wear 2 is going to support widgets on the watch.
Last night, I tore down the latest dev preview's ClockworkHomeGoogle.apk - the "home" app on Wear that runs your watch face, shows notifications, and provides other system-level UI functions. In it, I discovered a widget chooser, analogous to what you get when you long-press on an Android phone's home screen and select "Widgets". I've confirmed that it wasn't there in dev preview 1.
Right now, it doesn't do much, just shows a blank screen with "No widgets found". And it's not just that there aren't any widgets yet; I tried installing an app with an AppWidgetProvider, and still got "No widgets found". But clearly, Google is working on building this in to Wear.
In Wear 1.x, widgets were one of the few standard Android components that was explcitily excluded from the API. Wear 2 introduced a different sort of widget in watch face complications - they're not conventional Android widgets, but they perform a similar role, allowing you to show data and access functionality from various apps on your "home screen" (the watch face). And now, it looks like we're getting old-school widgets too.
It remains to be seen, of course, how Google will integrate widgets into Wear. Will it support some sort of "home screen" that's more like what you have on a phone, rather than a watch face? Or will widgets be integrated into watch faces, perhaps as an additional complication type? Or something else entirely? We'll just have to wait and see.
But if you're a Wear dev, you might want to start thinking about whether a widget would be right for your app.