You're all over-reacting. Seriously, grow up. They made some modifications.
Fun, you're in no position to complain about YouTube's channel layout. The only people they'll listen to are their Featured Authors, such as Machinima and Rooster Teeth, who get paid by YouTube to supply videos. I think they are enjoying it, as am I.
You can still watch a video on the user page, but why would you? You can't see comments or the full description. The video page is where all the action happens, so I'm only on user-pages for a couple seconds to locate a video faster...which, BTW, is easier now. The video tab is much more clear, and I don't have to find the button to display all the videos on one page. Everything looks more neat and tidy.
I will only accept criticisms from people who can use both GRAMMAR and CORRECT SPELLING. If not, thou shalt be mocked.