I was looking at using a book of ashur on my slann for my 2000 point army, and was wondering what people think of this idea? I will be using an EOTG so the idea of getting +6 overall to any casting sounds pretty sweet to me. (lvl.4) I figure I could dominate the magic phase, or at least have a lot lower odds of failing any spells. I could even cast some spells with one die and not have to worry about miscasting. I will be running life so Throne of Vines at 3+ on one dice sounds kinda dope.
you dont need the book to cast most spell with one die (plus the free one ofc). the average roll of 2 dice is 7, thus it becomes 11 after your normal +4. most life spells are very cheap, and you will dominate the magic phase in either case tbh. the book is just so expensive, you might aswell just get more units instead.
Dominating the magic phase with a slaan at 2000 points does not require a lot of help other than rumination and cogitation. With an EotG on the table, the casting values are lowered by 1 (it does not add +1 to your casting ) although I imagine you would be much better off using burning alignment or the protection ability. As LT has indicated, you could field an entire extra unit for the same cost and that would likely be far more useful.