The funniest part about this discussion regarding spell DCs is that if you play on unfair, unless you go the expanded arsenal bug abuse route you won't be able to land any DC based spells on enemies anyhow. With a DC of 74 on illusion spells there are still enemies which can make the will saves. The main reason angel and lich are so good, aside from massively boosting your CL, is because the angel and lich specific spells are good even if the enemy makes a save. I mean look at spells like this:
Good old, "save and do the same thing to the enemy." Or bolt of Justice which deals 1d12 damage/CL to the enemies which matter and a reflex save only prevents the enemy from being proned.