Makes sense to me for the way it is...
Mages and Necro by default will get beaten on. Necros also use there hps to power there magic, mages dont have a lot of ways to get themselves out of trouble once the mage himself comes under attack.
Wizard and enchanters have some tricks up there sleeves to remove themselves from the threat.
I can see were the Agil/sta split came... would sta be useful to wizard and enchanters? I just dont see it as a big deal.