It has always seemed counter-intuitive to me the way ESRI implement the default mouse scroll direction to be forward-roll, zoom out. However, every Desktop app, including ArcMap, ArcScene, ArcGlobe, ArcGIS Explorer and ArcReader, have always had an option somewhere in the Customise or Options menu to change this behaviour to forward-roll, zoom in.
Until recently, that is. This option has now been dropped from ArcReader since one of the early 10.x releases, and is driving me and my users nuts.
Can we please have this back?