I think this is the biggest problem with Berserker at the moment. It's not the only problem, but having to waste Berserker's Stance or take Signet of Fury just so you can get access to your class's main mechanic feels like a fundamental flaw. I think that Rage skills should still be giving Adrenaline when out of Berserk mode. The Warrior has a lot of Adrenaline generating tools, but they all compete with other vital skills/traits, and we always have to weigh them against just picking Spellbreaker.
Also, did you people know you have to land the Berserker activation AoE attack to proc the 3-stange burst passives? Cut us some slack Anet lol