Bah, if you really followed the rules in D&D 3.X, you had to roll randomly for your NPCs as well, so in the end it simply is the same as in D&D 4th edition if they're going to tell you how much hp the NPC should approximately have. If in D&D 3.X you should have 24d12 for an epic lich, that could range from 24 to 288 hitpoints. If they're going to simplify this and say that an epic lich level 24 should have between 150 and 220 hitpoints, it's going to be faster, and therefore better.
Only the people who really love to randomly roll hp are going to gripe about this, but I really couldn't care less for them, as I've played RPGs where you really rolled for everything (The Dark Eye 3.0). I'm not going back to those dark ages...