YouTube has finally removed the old grid view my_subscriptions page. If you don’t like the frankly broken and unusable /feed/subscriptions page, there is a Chrome extension that will fix it for you.
Better Youtube Subscriptions Page
“Transforms Youtube’s broken feed subscription page and restore it to it’s former grid glory.”
In fact, I actually prefer it over the old grid page because it fills the grid to the width of the page, showing more on wider resolutions. It doesn’t seem to hide watched videos, but I didn’t like the grid page doing that anyway because it also hid partially watched videos (anything viewed for more than a couple of seconds).
This app does not require strange permissions that it shouldn’t need or an OAuth login (as YouTube Video Deck does) or anything like that, it just alters your subscription feed to appear as a grid.
As a side note, the YouTube API actually doesn’t need authentication to get channel or video information. You should only need to give login auth if it tracks what you have watched, automatically gets your subscriptions from your YouTube account or anything else that involves your account directly. Although it’s better than a 3rd party website saving your password, you should still be very careful who you give your OAuth authentication to, as it essentially logs them into your Google account for you.
It’s also compatible with the YouTube Ratings Preview extension, which shows the green/red rating bar on the thumbnail before you view the video, although this seems to only show ratings previews on the first 30 or so videos on each page.