Great article, Tom. Insightful and motivational too.
I second the idea of the product manager being the representative of end users and also the go to guy for different teams (Engineering, UX, Architecture) working together on a project.
Also, the PM’s job is to effectively unblock people. Artists, designers and geeks love their freedom and concentration and its the PM’s responsibility to make sure that they are least impacted if and when they are blocked.
I too have written about the attitude and soft skills needed for a PM — https://gautamdhameja.com/the-product-manager-attitude-302c8920f41b#.5wqde4aki
Please have a look and share your thoughts. :)