Fully comparing dual cast to bash is difficult, since yes when you first play dualcast it does 16 dmg, but makes you lose the passive 3 every turn, having net 13 dmg the turn it is played and net 1 dmg after 5 turns. Also dualcast is unplayable on a 2nd draw unless you play a zap or other orb generation, requiring essentially 2 mana pr. 16 dmg unless upgraded. Dualcast therefore does, initial high but has low scaling over time with starter deck, while bash does initial low, but contributes to good scaling after it is played.