I cannot confirm your impression that logging had been made complicate in WildFly.
I've just unpacked the wildfly-8.2.1.Final.zip, added the administrator account and run ./standalone.sh -c standalone-full.xml.
Then deployed a war containing a servlet where I just added the 2 lines
private static final Logger log = Logger.getLogger("ServletName");
log.info("The information to be logged ...");
I did no configuration at all.
Can you post the stack trace of the ClassNotFoundException? Deployments generally shouldn't see the log manager's Level class, only the main j.u.l one.