This would be really useful for me too, especially the string substitution as we need to deploy to development, demo and live systems. We've had to fall back to Ant / Maven tasks instead of using the servers window for this.
I think an extra screen on the deployment configuration is all that would required for this. On this screen could be two lists - one to enter a list of files to apply substitutions to, and another list to enter a selection of .properties files within the project which contain the strings to use for various deployment scenarios.
When creating a WAR file it could then ask which of the .properties file to load the strings from.
In hibernate.cfg.xml we could specify
Then configure the list of .properties files as:
Here's a couple of mockups as an example of how it could work:
Somewhere in configuration of a deployment:
After clicking redeploy in server window:
Alternatively the option to run an Ant or Maven task before deployment would be useful too.