When I saw warlocks had the ability to freeze opponents permanently, I was fascinated with the idea. I thought it would be COOL (pun intended.)
But in Epic quests, not so much--nevermind on Legendary. There's no way to scale these up except by raising your primary stat, and with the stat squish, that actually means Absolute Zero is even less effective. Sure, it kills fire creatures no save, but I notice at high levels there aren't many of those.
At least give Absolute Zero and the other Warlock abilities similar to it some bonus that can be mitigated by feats and equipment. Please?