1) Occultism is better at big and devastating spells. And as I said, Sorcerers secret pact with the Dark Gods prevents them from heaving it, it is BGT related2 Questions then:
1) Thaumaturgy have literary the biggest devastating spell in the game (wrath of god) and ogres (who has small spell strength) have access to it? Don't you find it to be quite weird?
2) ADT wanted barb caster - why he didn't made it? For book about warriors we have quite a lot of barbarian stuff, barb chief for example was nerfed into the ground anyway.
2) Because this is a Warrior book. Executives did not want more Barbarian entries than there already are. From RT point of view we would probably not be allowed to have 4 or even more Path access to begin with, because that is only for armies with strong magic theme and WDG is not one of them. We are allowed three and a half.
Personally, if you are not a tournament player I see no problem heaving an Asklander caster with your WDG. Rules are there to create a frame for you to play what ever you want. Like D&D.
Where I can find info about this pact? For there are nothing about it in Paths of Magic, and none in warriors book.
PS: Unfortunatelly - i am tournament player, and majority of players in my region play in tournaments too. So it is hard to find a person who would want to waste an opportunity to play a game that will not help him even in a slightest to taste what he can actually encounter at tournament.