I used to be a big fan of the vast intellect trait for my slann, but have been testing out arcane might in a few games of aos2. With the importance of magic and with how you only get to cast or unbind each thing once, being able to reroll that critical unbind is really strong. In aos1 this would have left your slann without enough spells to cast but now I'm finding I just bank 6 celestial points a turn and pop out some skinks or terradons. The global unbind is still really good, I figured it would have been watered down, but there is actually plenty of board outside of 30" if you're playing some of the spread out battle plans.