The system itself was not significantly changed. The major improvement is that almost all AA are handled in via the dbase tables and not hard coded in the source.
For more details see the change log .
http://projecteqemu.googlecode.com/s.../changelog.txt
I started a wiki page for little more details on how it all works. Might be of use.
http://www.eqemulator.net/wiki/wikka.php?wakka=AAInfo
Kayen