Scrolling a mouse wheel toward you is a learned skill that you do without thinking, that is, unless it zooms out in some applications and zooms in with others. Its a bit like riding a bike and you don't want to think about it too much. One suggestion is to pick a zoom direction that is intuitive to the majority of users and make all applications use that zoom direction starting at 10.1.
What currently happens when you scroll the top of a mouse wheel towards you: Arcmap. ArcGlobe - zoom in ArcGIS Web Apis, Yahoo, ArcGIS.com web map, Arcgisonline, ArcLogistic Online - zoom out