Just seen this as well. I hope they don't get rid of the like button, I've got a massive list of videos I've yet to watch on my "liked videos" section
That's... not how you do it? There's literally a 'watch later' option. Likes are for when you, you know, like what you've seen.
On balance I think I'd take away any of those 'instant reaction' buttons from the internet as a whole, both positive and negative. I've seen some stupid strops online of people threatening to delete accounts because their subscribers weren't liking enough of their content etc. It's made the world mad, seeking this instant gratification after putting trash online.
With regard to things like technical 'how-tos' getting dislikes/downvotes as a way of warning people off them, then you'd have to keep a reporting function for inaccurate or dangerous guidance, although I'm not sure how a random YT moderator is going to be able to police that without themselves referring back to online videos.