Viewsheds (Line-of-Sight or Area-of-Sight) as an associated utility for TNP.
The need for Viewsheds is rapidly increasing in the SAR world esp. for searches for cell phones, in addition to uses as in the suggestion "Radius Tool or Tower Tool" ). Even the simplest Line-of-Sight model that generates overlays would be valuable using the DEM already built-in to TNP (MTH). A utility that functions along with, but not yet fully integrated in, TNP (as TNP's FormatMXF.exe utility) should be relatively easy to include as a feature of TNP and would be a selling point for TNP.
Better elevation data might be imported and used in the utility (e.g. GridFloat and DEM). (See other suggestions on contours and elevation data import.)