If we think of Dr. Shapiro's work on Big T and little t traumas, we can help people explore the subjective nature of classifying an event as traumatic. Further, thinking about concepts such as temperament and resilience further complicates the creation of a single list. One person's subjective experiencing of an event, could be significantly different than another's. Thus the difficulty in what constitutes an adverse experience.
While this may seem as an impediment, as a helper, I find it liberating. I don't have to concern myself with defining an ACE for my client, she can do the defining...and explore resolution.
Hope this helps...