In the blog post Updating Navigation for Stack Overflow, Enterprise, and Stack Exchange Sites the term "information architecture" is used to justify the inclusion of a new section for all Stack Exchange sites as shown below.
PLEASE do not use this approach. It is dangerous to damage the flagship product in order to test the channels feature, and this would be damaging. It would literally be removing a large section of the most prominent part of the viewing screen. Put simply, this change will make the site harder to use.
The response to similar concerns to mine was that "any concerns about the extra screen width this would introduce were alleviated with knowing that the site will become responsive". That just means "the sidebar will take a larger percent of the screen the smaller your screen gets", and absolutely does not alleviate any concern I have.
This change will make it harder to place ads on the existing sidebar as its size will be impacted, make it harder for users to navigate the question list as there will be less real estate per abstract, and will not get anything in return aside from moving a horizontal set of options to a vertical one. There is quite a lot of information in the multi-collider, why can't this approach be used for features?
Moreover, why is the approach to make a channel silently look like Stack Overflow when it is not? I would suggest that there be a path to migration from a channel to other exchanges, and that the channel itself look like a separate exchange from Stack Overflow with a default gravatar image that can be replaced with an uploaded icon for the channel.
This would allow a seamless experience so users are not confused which site they are on, reduce the need to re-engineer the entire exchange, allow channel customers to retain some branding, and allow the team to focus on more important tasks than dealing with the implications of modifying every single view.