The existing documentation should be more clear that bower is optional and not necessary on new projects. The places in documentation that I would change are:
Overview: Says that npm and bower are used, but lists bower first. I would rewrite this entire paragraph to be more specific.
Getting Started: Says "you'll need to globally install bower". I believe the section titled "Bower" can be removed entirely
Managing Dependencies: Fairly clear that bower is optional. I would add a sentence saying that its use is deprecated.
The existing documentation should be more clear that bower is optional and not necessary on new projects. The places in documentation that I would change are: