mmkay. Sorry, hope I didn't come off as 'that guy' :P
The perfect bab/saves, beastly hp and sp combined with very strong SU casting that is competitive with a divine caster of equal level. The Excellency ability to permanently buff an ability score by 2 alone is stonger than anything the wizard has in their kit.
The wizard is better on offense, but is much squishier and has saving throws which negate their abilities.
I agree it's a very fun class, an awesome villain, but just like the P-classes in BoVD, perhaps not intended as a party member.