I think it's applicable to other situations as well. Even if you're selling something and hope to guide visitors down a funnel, an accurate time-on-last-page metric should be valuable. There's a world of difference between someone that bounced immediately and someone that read your landing page for a few minutes but wasn't convinced to take the next step.
I don't understand why you have to redefine the term "bounce" in order to achieve that. You could simply say that "bounce" wasn't the metric that you were looking for, or that people put too much emphasis in it. You don't need to "fix" it because it isn't broken.
"Bounce" is a measurement of people that do not continue to interact with a site after the first page they visit.
Most of them take a very pessimistic view. I believe Google Analytics counts a single pageview visitor as 0s, for example. That turns out to be terribly inaccurate for my site.
Not in all cases. For an affiliate site, a bounce could be some one who gave up reading, or someone who was completely sold and clicked through on the affiliate link. They both show up as "bounces" in Google Analytics.
While I appreciate the sentiment, I consider "bounces" to be a lack of up-sell. My stats give me a "bounce" rate as well as the average time spent on that page for new visitors, so I can already see both of the stats he's referring to. They are just useful for different things.