In D2 the amount of potions you can carry is limited by inventory space. At end-game you want your entire inventory filled with charms/anni/torch.
But yes people complained about balance in D2 because you could abuse TP. Even with TP abuse though Duriel is harder than anything I have encountered in KOA by a million times.
Each potion in amalur takes up inventory space as well... probably not enough.
Oh god, Duriel on Hell mode /shivers
I think that was basically because he'd knock down your whole health bar in like a single swing, and he had a unbreakable snare on you all the time. Not exactly my idea of good boss mechanics, but they were effective (at making me rage)