Changes are only visible if you watch the video in full-screen mode. The app looks almost like watching a video in portrait mode. However, this had the advantage of easy access to share buttons and other controls. You can see that in landscape mode as well.
Also, you can now easily access the mode where you can view comments with the video in landscape mode. Before the new UI, you had to tap the comment pane in portrait mode to open it and switch to full-screen mode. You can now access it by tapping the comment button.
