Yeh, the Rock armor > Stone Fist > Earthquake and Winter's Grap > Cone of Cold lines are really overpowered in the game. Cone of Cold has only a cooldown of 10 s, so you can just freeze a lot of enemies, shatter them with stone fist or let your tank crush them, then when the freezing has run off you can simply cast it again.
I picked those along with Mind Blast > Crushing Prison and had no problems. Sleep + Horror is a nice combo to pick up as well in the long run.
I switch party members a lot because I love their interaction. I think the dialogues & characters are the best in any BioWare game since BG 2.
