I never minded Soma winning out over evil. It felt like Mathias was redeemed, and can live out his life as a human, with Mina.
At least for Aria's ending it felt better. Specially what with Aluc-er-'Arikado' thanking Soma in his Mother's name, for defeating the chaotic flow of power which kept Dracula and his castle's vicious cycle going, therefore denying his destiny and ending the threat of Dracula ever coming to pass again.
But Dawn presented the better Dracula scenario- where Mina is supposedly killed, filling Soma with enough anger to begin absorbing the chaos around him, mirroring how Mathias became Dracula after Elizabetha was killed, and declared war on humanity after Lisa was killed. It would be Dracula being reborn into Evil once again after the death of his third.