Arctic armor: I know that Ice King / Demon were available, but that doesn't make the concept of the ability useful.
Fashion Plate requires you to spend 15! points in Armour Specialist, so I would be expecting that this char will be wearing heavy armor. The best Sarongs only need 10 Int and often come with a +2 Int bonus. You hardly want to equip staffs when you have a low int (same thing for Bows. I could only see this being used on a high int char that insists on getting the highest physical defense possible. A more offensive build with heavy armor would have transformed the talent ans AS points for +3 STR and level 4 Man-at-Arms for stuff like Nullify Resistance.
Adaption: The bonus from Rubies scales with the level of the item. Level 18+ (17+?) equipment means a +25% bonus
You are forgetting that the alternative +2 SPD would give you +1 TAP
Lets say you have x AP during the first and y AP during the second turn without any modifiers (total: x+y).
With HS your AP will during the first 2 turns will look like this: x+3, y-1 = x+y+2
With +2 SPD your AP will during the first 2 turns will look like this: x+1, y+1 = x+y+2
So you will have less AP in every battle that lasts more than 3 turns if you choose this instead of investing in Attribute points.
People will spend more heavily in Witchcraft when you give them a reason to. Making your char immune to physical damage is a damn good reason to do so.
Lone Wolf: Yes you can boost your attacks to get a difficulty of 150, but I don't think that the enemies can.
Tenebrium: I am sacrificing 30% extra damage in Cyseal so that I can have 30% more damage on the other 3 maps and be highly flexible regarding my weapon types. That seems to be a really good long term choice.