This is a good approach, and I'd like to suggest another approach. Define the desired outcome(s) prior to development and hold any candidate release to that standard. What's the probability that the product in its current state can achieve those outcomes?
Note the focus on probability: The goal isn't to achieve a consensus on release vs. don't release. It's to agree on the likelihood of success if it is released. It's a subtle but important distinction IMO. If you can agree on probability of success, then you can have a much more fluid conversation around shipping, rather than being forced to choose an extreme.
The challenge of using good vs. great as a metric is that those terms are very subjective and susceptible to change depending on circumstances, roles, motives and personalities. While you can agree to define those terms in advance, do those definitions then become too constrictive? With outcomes, you can focus less on what you're shipping and more on the effects of shipping the product.
Of course, I could be wrong on this approach. Thanks to your article, it helped me think through it a bit more, so I appreciate you sharing it.
I think when defining “good vs. great” as metrics, it is vert important to remember:
Your product is only as good as the value people get from using it.
With this as a guiding principle, you can really focus on the relationship that users have with the product. That’s where value is defined. From there you can identify what dimensions of the experience will likely have the greatest impact in getting the user to find that value, and when to emphasize what.
If you consider that you are essentially selling users to “yes” in each interaction—with the question being “Is this interaction fulfilling my needs and expectations for ___?”—you can really focus your efforts on the primary aspects of the product that answer that question in that moment.
In that context, a useful way to define good and great might look something like:
Good: the user’s needs and expectations are met and they are able to achieve their goals without confusion or frustration.
Great: the user’s needs and expectations are met and they are left with a feeling of accomplishment and satisfaction from using the product.
Here, the distinction lies in how the impression that the user leaves the experience with. And I hold that enough “great enough” interactions within a product compound to what may ultimately be perceived as a “perfect” experience.