Dumma pretty much covered it... Especially Tetra Punch, which it's your haxx 1:1 skill for a Boxer/Duelist.
Though for Berseker.. It will help, but when casting it, you can not control your character for a certain ammount of time. While considering Berserker, focus on getting your prefered AoE skills from the Warrior tree. (I always like Inferno x Earthquake more.)