I dislike Youtube's new look. Not entirely, those some good things, but I have a 1920x1080 screen and the amount of blank space is ridiculous, and all of it is my right hand side of the screen. Also I want my default home screen to be my subscriptions, and all the uploads they've done recently, not this "what to watch" thing that recommends me things it says i've already watched.
Google in general has been giving the Mickey Mouse treatment to all of their interfaces. They dumbed down search options, particularly image search, and took away a lot of the advanced options. They also removed the ability to view someones youtube uploads by a numbered page view, so you could say, skip 5 pages ahead at a time rather than having to load each and every page, which takes forever.
And I just plain do not like the new Youtube interface. It's just dumb.
I think Google is losing track of what used to make it awesome and now it's just copying what everyone else is doing: treating the customer like a ****ing moron.