Does channel design matter?

Exactly its like if you go into a shop and everything is displayed wrong and looks dumped on the shelves your least likely to buy anything. I should know I work in retail. If your intent on displaying your videos and increasing views then you should have a proper layout or even an avatar picture that's your own
Calm colours that match to what you actually are making videos of.
Like your having a video about a song then it would be bad having alot of explotions and dying people around it.
I like to stay with mine calm.
I agree, when a channel has a horrible layout, background, and things like that, it makes me not want to watch their videos. So even before saying 'If the content is good, I don't care', I'd say: I'm not even going to watch in the first place if everything else looks horrible.
The channels looks should always represent the production value of the channel.

However, I don't care about the way channels looks once I like them, I just won't watch videos on bad looking channels.