I do wonder if berserking monsters has actually been bugged for a long time, now that I see what it's supposed to do; 'blind rage' monsters seem to get WAY more than double attacks. The gnoll that killed me went from 2 attacks to 9+ (the 9th killed me). Even if my speed gave it two turns between mine and its attacks doubled from two to four, it should only get eight.
Either way I'm happy to see a moderate nerf to this; blind raging monsters are one of my more common and unpredictable YASDs. You tool up to be safe to be in the area you're adventuring in, you fight a monster that you've killed 10 of already, and suddenly it instagibs you from high HP - always felt a bit unfair to me.