Sure Spell for the Ice Wall and Frost Pillar cast (Ice Wall can be a pain in the ass to fire off), Sleep because it’s good CC, 1 rank specifically on Energy Bolt because the attribute lets it hit hard against sleeping targets (used in between cooldowns), Magic Missile because it’s hilarious, dumping the rest of those points into Lethargy because Lethargy.
Warlock is for the nukes, I’m not concerned with the shield so I took invocation instead, Evil Sacrifice seems like a slow cast (based on the video provided).
Quick Cast: you’re right, I’d take 5 off Lethargy for that.
Edit: only 1 point in Frost pillar because every point after level 1 only tacks on 1 second to the lasting duration, not much too it. But I wouldn’t mind trading Snow Rolling for max Frost Pillar