In EAP 7.0 with security subsystem there is possible to setup security domain which uses "UsersRoles" login module. This module allows to define users and roles properties directly in deployment specific for given application.

In Elytron subsystem introduced with EAP 7.1.0.DR4 the most similar one is properties-realm, which requires to have the users and roles properties defined in file system, it doesn't allow to have them defined only in the deployment.

As Elytron is supposed to be replacement for security subsystem and this is quite commonly used login module, I am considering this as critical bug.