When I click the "X" on the upper left so the sidebar goes away, then the design gets way better. It's almost good then. And good design is hard to find these days.
The only thing that then still looks annoying to me is the "Recommended channel" thing. Make that go away too and I am a fan of the design.
Here comes my feedback:
You should get rid of the forced "Subscribe to channels" page. That made me hate you.
Filter by "all channels" was hard to find.
I hate endless scroll. Would prefer paginated.
The comment pages look strange and bulky.