It would be nice to have an on-screen zoom slider and vantage point control.
Zoom Slider: Yes, you can use your mouse or mouse pad on a laptop, but sometimes a zoom slider is more useful.
Vantage Point: Sometimes the program zooms-in at an oblique angle. As far as I've found, a user has to click the Home icon to return to a nadir view and then zoom back in. This tool would allow a user to change their viewing angle as needed.