All the YT apps I have tried in the past have failed because it seems YT alter the API so often that developers just give up trying to fix what YT break too often. SO i would assume that this will break all existing apps and some will again die off. No doubt the new features will make it into the API, but at a cost to users and developers.
Yeah, I've seen multiple great YouTube-apps die because of that. The best-functioning YouTube-app that I currently know, actually scrapes the webpage to get its information. It can't do subscriptions because of that, but I can easily replace that with an RSS Reader.
