I would love to see application templates automatically be deployed to nodes where they don't already exist based on rules. I imagine building these rules would be essentially the same as building Alerts but the action would be to apply the application template.
For example, I could create a rule that says if the node is Windows and Custom Node Property "Environment" is set to Compliance and monitoring type is SNMP then deploy my Application Template called "Windows Compliance Apps (SNMP)". I could then set that rule to run once every 6 hours so any nodes that match would have the necessary application template deployed.