These are some of the hardest to get items in the game. Their stats should reflect that. In the time it took me to collect the 1000 pelts for the Black-Ice staff, I found 5 other Brain Freeze staffs, and a ton of other stuff. Unfortunately, this meant that the black ice staff was no more than a showpiece as soon as I got it since the Ice Blast staff actually has better stats. As is they are mostly identical to the regular Iceberg, Brain-Freeze, and Shivering gear that drops in Frozen Nightmare. The Black-Ice staff is actually inferior, with 1 less armor than the Brain-Freeze Ice Blast Staff. I think the items should be slightly improved to make them more desirable, and the staff should definitely be at least as good as the regular one.