Struts2 action methods should accept arguments just like JAX-RS specs. Also certain method types should be allowed only like GET, PUT, POST, DELTE.
Inspiration might be taken from struts-json plugin @SMDMthod but that is not a real action method.
If there are multiple action methods in a Action class then it becomes less obvious which variables are used for a particular action method.
Also flexible return types as defined in JAX-RS would be great or atleast
The action method return type can be to denote builder like result. The closest in struts I can see is HttpHeaderResult. But this does not allow arbritrary string result and let the end user create the string as json or plain text.
Inspiration can be taken from struts2-json-plugin#SMDMethod and https://github.com/bastengao/struts2-freeroute