Please build in installed application detection
Currently if you modify an existing software deployment, DC will attempt to reinstall software that is has already installed previously. This forces one to create another group or targeting so this doesn't happen. Support has told me the best way to detect if an application has been installed is to implement a pre-install script which is OK but it would be better if some kind of facility could be built in to check for some common conditions such as the existence of a file, existence of a registry key or value, or the ability too check whether the program exists in "Programs & Features" or "Add/Remove computers". This would allow me to modify a deployment but not have to worry about repeat installs to existing clients that still meet the targeting criteria.
I feel this is a major hole in the product that is covered by other software deployment platforms