Considering these issues, would anyone use a Chrome extension that would allow them to hover over a YT video thumbnail and see a summary of the video transcript? The user could then choose to either watch the video (based on the summary) or dislike it. This makes it easier to bulk dislike videos and tune your algorithm without investing several minutes to click a video, wait for the ads to be done, see the intro, then dislike, click back, and restart your browsing experience.
So, for the main page (and recommendations) of YT it's already done. How your idea is different from this?