Hi Yacine.
In principle it is possible to build the installer with WIX without Visual Studio installed at all, i.e. VS is not required to build installer..
You could simply run MSBUILD for the solution from the command line, and that's it.
The template could be improved to not require WiX to be installed in VS, but use whatever installer VS got..
Anyways,
I think ideal to solve this problem with installations "
once and for all"

could be something like WebApps in JavaScript/HTML and store online.
So that the app
- can be modified centrally for all users.
- (almost) no installation
- will be compatible with online version of the Visio (if it ever comes, yea)
- it is easy to build rich user interface with HTML
What would you think about this idea (it's about macroces, but I think it wold be better to speak about "web-based" apps - like in a panel in Visio for example)?
http://visguy.com/vgforum/index.php?topic=5238.msg20657