Engineering for Evolution
The criteria for engineering a good user experience spans across diverse incentives.
Ease of use is the most well known one, but I find it to be subjective. A cognitive device that helps me when in the development cycle is a flavor of iterating with the question of “how do I make this more intuitive?”. This follows from the realization that even for measurement along qualitative dimensions, we generally find comparing two entities (and ranking them higher/lower) easier than to come up with an absolute measure of that quality and resuming with a global sort. Working on concrete iterations also allows me explicitly think out loud in terms of what worked and what did not and then abstract later on for future wisdom.