I've launched a small Grails site a few month back and now I have to deploy incremental changes to the app, most of them not involving any db changes. New tags, bug fixes in controllers, services, ect. Right now I'm simply picking through the haggis of classes and artifacts generated by running grails war SOME-WAR.war and manually dropping them into production environment. You're probably right in your sentiments at the moment and believe me this process is quite the punishment in itself.
Any suggestions on improving upon this?
There is a way, althought I would only recommend it if the changes are small, take a look at this: http://grails.1312388.n4.nabble.com/Build-pre-expanded-war-file-td3337931.html
You can not incrementally update a Grails project like you can a php project or other intrepreted language based project since java is a compiled language.
You can use ant deploy scripts to automate the deployment process. I use the remote deployment plugin for Jenkins for this task.