Well, you don't really want to make him any more expensive. I see the strength on DfIA a bit different. Just look at this from the opponent's perspective. Yes, you could deal 2 wound to him and has slight chance to kill, you can do like 9 wounds and have 50/50 chance to kill him. But there's also a big chance just to waste of all this damage. IDK, if I'd played against such a model, I would simply try to ignore it. Remember, that he will have cover, lookout, astrolith and guard on top of it. I still like 4+ FNP more, but the new ability is not as horrible as it may seem. Old kroak had bravery 10 and rolled single d6, iirc, so you had to deal at least 5 wound to him, to kill. But that was per turn, not per phase. And he was quite popular. I can think of 2 main threats to kroak now - Teclis with his AoE spell, since he loses nothing, if he hits kroak and he can deal up to 6 wounds, and Kharadron alphastrike lists. I like the fact, that he knows all the lore, but still don't have access to skink one. However, a bit more spells can see play, like walk between realms and drain magic. I still wish he'd be god-like strength model, which can compete with teclis and nagash in terms of magic mastery, even if he wouldn't be so competitive. I think, we will more actively use arcane vassal now. Maybe, trogg will see more play?