Looks like you learned the hard way about hovering over to expose features. If you've got touch screen users those features will be virtually useless as well.

One thing that would have been cool to see your writeup would be how you used direct customer feedback. Maybe it was none at all, but I suspect talking to customers (or even internal employees) helped you reach some of the conclusions you made. It's really difficult to look at a graph and go, yes this is the thing that caused the change.