All in all, there's a lot to like here, but it isn't perfect. A test video file I uploaded a few weeks ago wouldn't display in the preview pane the day these features were announced, for example. All I saw was a spinning progress display. Additionally, thumbnail previews that should have appeared in the controller at the bottom of the pictures slideshow were absent. I began to wonder if Google hadn't rolled out these new features too early. Throughout my testing I used the Google Chrome browser. I have to presume Google tested its online software in its own browser.
Additionally, previous predictions about the preview pane being a multimedia jukebox of sorts haven't come true; you can't play MP3 files uploaded to the Docs space, for example, and there's no way of creating a playlist. Ah well; maybe next time.
Because of this, the new organizational tools indicate that we're no closer to the concept of a true "G-drive" in which Google offers file playback and viewing facilities for any kind of file or document that users upload to its cloud. It's pretty clear that, at least for now, Google Docs still very much focuses on office documents, plus image and video files.
Note that not all account holders will get the new features immediately, although various Google accounts I use (including Google Apps for Business accounts) all featured the new setup immediately.
Keir Thomas has been writing about computing since the last century, and more recently has written several best-selling books. You can learn more about him at http://keirthomas.com and his Twitter feed is @keirthomas.