Deploying our ear on jboss-as-7.1.1-Final, we see about 32,692 classes loaded when we deploy our application ear (based on adding -XX:+TraceClassLoading to our jvm arguments).
Deploying the same ear to jboss-eap-6.3.1, we see 203,962 classes loaded (and we get OutOfMemory PermGen errors unless we set -XX:MaxPermSize=2g). Analyzing the detail of the TraceClassLoading output, I see one class (a base class to several apt-generated anonymous inner classes) loaded 39,443 times alone (all but once "from __JVM_DefineClass__"), with several other classes loaded over 1000 times, and many many classes loaded more than 10 times.
So, that seems like something that we have configured incorrectly in eap-6.3, but we haven't been able to find the error after a few days of searching. My standalone.xml from both as-7.1.1 and eap-6.3 are attached.