Creatures that used to "Frenzy" like Magmadar, Gluth, Princess Huhuran, Halazzi, etc. now "Enrage" instead. Tranquilizing Shot has been changed to dispel Enrage effects, and the wording on all those spells and associated emotes has been changed to reflect the name change to Enrage.
Creatures that used to "Enrage", now "Frenzy" instead. This is the type of effect that typically happened at low health or some other combat trigger. Examples of this would be all the Blackrock Orcs in Redridge, Jan'alai's low health/timed increase in damage, Maexxna at low health, etc. These effects are not dispellable, you are meant to deal with the increased damage as part of the fight.
Many of our boss encounters have timers where if you do not defeat the encounter within the allotted time, the boss will suddenly do RADICALLY more damage. Players are not intended to be able to deal with the damage dealt by a Berserk boss, and a wipe should be around the corner. We try not to use the "Berserk" term for nothing else but these kinds of timers.