Description of problem:
Drools jars (engine) are missing in jboss-as-web/client directory in standalone BRMS distribution. I am not sure if they should be there, however they were present in 5.1.0 GA standalone.
Version-Release number of selected component (if applicable):
BRMS 5.2.0 (all builds)
Indeed, the issue shall be fixed for 5.2. It would be available in next release.
Verified fixed in 5.2.0 ER4.