Should we align with the Servlet Mapping in the spec or the way JAX-RS does it? They're similar yes, but somewhat different.
I don't know the differences between Servlet mapping and JAX-RS, but I vote for the Servlet mapping. I'd say the most common use case will be a light-weight alternative to servlets.
In fact it would be ideal if @Path worked the same way as @WebServlet(urlPattern="/your/pattern/here").