As far as I know, there are almost no custom hooks required to handle our VFS with AS7/Wildfly, based on my experience with this example: https://github.com/jboss-jdf/jboss-as-quickstart/tree/master/kitchensink-spring/basic.
So users are not required to use -spring.xml to deploy spring apps.
Besides the custom hook, some of the options we looked into are AOP (too much configuration required on user's part) and javassist (not possible). We are now looking at Byteman, thanks to Vineet's suggestion. If we go this route then there would be no need for custom hooks, but would happen without users knowing, which may be a problem for some. What do you think?