Three great ideas here...
1. How about allowing pasted links from YouTube videos to automatically display their preview panels! You know, like I've been doing for over a decade until this latest forced update.
2. How about, in the future, not eliminating features we've been using for years and referring to them as "new" or "improved" Yahoo changes! Eliminating the YouTube preview panels may be "new," but does it not "improve" Yahoo Mail for me.
3. Allow users the choice to continue using the previous version! You know, like I was able to do when you rolled out all previous "new" or "improved" versions. From a user's perspective, dropping the preview panel feature in the YouTube links neither "improves" Yahoo Mail nor in any way makes it "better." Yahoo Mail has been my primary email provider since the day I started using it. You finally "improved it enough" to motivate me to consider making Gmail my primary account.