I think sub-zero smash is cone, but a very narrow cone aoe. I had a few orcs in campaign just how get hit with it and they weren't quite in the same line of attack.. I'll show you.
....X....X
......X
......
.......X
..........O
The X's are orc's, I'm the O. I was facing north westish where if the attack was linear, it could hit all 3 of those orcs in line, but it hit a 4th one just slightly off to the right. Needless to say, I got ganked. lol

These orcs has not seen mah bukkit. D:
Also, the para proc'd on them all and lasted about 2 min or so. I like this spell as well as roar, which I use prior to a WS since keeping it up full time would be a pain and a bit mp costly. Plus I like the +3 STR for 3 points, it beats keeping heat breath set.