xml -- the configuration files are in an xml-like syntax. Therefore the parser reads this syntax and not xml. FWIW, it is a little easier to get the data back out for use.
User can choose to skip an installation and continue on to the next one. You can also edit the startup file, or write your own in a few minutes so it only includes the applications you need.
use variables -- easy to add variables to the configuration file, then use them later on. Like Ant, but interactively queries the user if they need to alter the default values of the variables. It would be nice to have a mode where you could skip the querying routine (easy but isn't done yet).
tclwebtest -- easily work with this by executing a script, which app-install could download. app-install could actually wrap this command line tool so users could easily change the defaults, without trying to figure out what the command line options are.
My next attempt to improve this will probably be to create a localized copy of all the needed files, and write an updated installation script before installation begins.
I also want to use sudo to execute every command as a particular user.