When hovering on a feature class only type and path are shown in the catalog pane.
However, I would like to get more information without adding a feature class to Table of Contents (TOC). For example, I would like to be able to see a little description, feature count, fields and/or inset map etc. We have about 800 different feature classes. Sometimes I need to open 6-7 different feature classes till I found the right one. I am sure there is many GIS users dealing with vast amount of feature classes/shapefiles or layers. Seeing the content of the spatial data beforehand will help us to save time and energy.
If you can make this tooltip adjustable, it would be even better. In that way, a user can adjust the information s/he would like to see when mouse hover on spatial data.