Don Norman and Jakob Nielsen see user-interaction chaos in new gestural devices:
In Apple Mail, to delete an unread item, swipe right across the unopened mail and a dialog appears, allowing you to delete the item. Open the email and the same operation has no result. In the Apple calendar, the operation does not work. How is anyone to know, first, that this magical gesture exists, and second, whether it operates in any particular setting?
With the Android, pressing and holding on an unopened email brings up a menu which allows, among other items, deletion. Open the email and the same operation has no result. In the Google calendar, the same operation has no result. How is anyone to know, first, that this magical gesture exists, and second, whether it operates in any particular setting?
Whenever we discus these examples with others, we invariably get two reactions. One is "gee, I didn't know that." The other is, "did you know that if you this (followed by some exotic swipe, multi-fingered tap, or prolonged touch) that the following happens?" Usually it is then our turn to look surprised and say "no we didn't know that." This is no way to have people learn how to use a system.
Norman and Nielsen point to some real design flaws, but aren't the new conventions developing pretty rapidly, and aren't people also figuring them out pretty rapidly? (The one unforgivable sin in UI design, though, is when there's no undo for a destructive action.)