Youtube. Do you see this? Do you see this horrible backlash? Take off your happy-goggles for a second and look. Nobody likes these. Nobody. You've taken about 15 steps backwards with these. I typo'd that as 150, but I think even that describes this pretty well! You crowded up the homepage, making it incredibly hard to use. I'm quite used to looking up at the top of the page to see I got some comments. It's pretty disorienting when you move that lower-left, isn't it? Secondly, you took everything good from the channels. The customization, for example. I take pride in the lovely backgrounds I dig up for my channel. So to make it easier for visitors to see, I set the background transparency so my visitors can see it. Now then, do you see what these channels lack? Is it a transparency option? Why yes, it is! Also, I have PMs set to receive only from my friends, since spam is annoying. So if I do communicate with people outside my circle of friends, I typically do it through my channel comments. Of course, you removed that too. Last is the video pages, and to be honest, I have nothing to say about that. Except that maybe some borders would be nice.
In conclusion, I will agree with everyone prior. The old Youtube worked. It was not this broken down mess of code. As everyone else has said, "If it ain't broke, don't fix it." Print that out and pin it up all over the office, if you would please.