I think the term "power users" is not appropriate. I believe we're encountering some kind of "curse of multidimensionality" problem here: every time Google adds

I think the term "power users" is not appropriate. I believe we're encountering some kind of "curse of multidimensionality" problem here: every time Google adds a feature, they add one dimension to the space of utility of their product. And every time they remove a feature, they reduce the relative volume of people who still find the product useful. So it's not "power users" in general, but "power users of feature X". There are not the power users who use all the advanced features on one side, and the regular users who use none on the other. The more features you add or cut, the more each of those categories tend to zero. Actual users are somewhere in between, and if you optimize against "power users" you in fact optimize against your users in general.