ATTENTION EVERYONE!
True, you can't delete vids that have a vote/comment or are older than 7 days... but you can do something amazing now ;) You can now edit your video's info and update the hash to show a current/pinned video.
Now in my case, I don't have those old videos anymore, so my links are pretty useless... what I did was I retitled the videos as "Expired" and replaced the snap hash with random type (sdjfka) and updated... the channel now shows a gray box and the title "Expired" for all my dead videos. It's still a bit cluttered, but it's better than people going to my channel and clicking vids that they'd think were still working but aren't...
Let's ask the devs for a soft delete that at least hides our dead vids from public view, thus cleaning up our channels.