I really like that idea and the thought process behind it, as well as the stigma that goes with it as an ancient ritual. But this then begs the question - when/where did they start to evolve from humans? And what could have triggered the evolution, as it takes millennia to evolve. Or perhaps we don't need to get so philosophical about it! XD

If Vail isn't willing to take the risk, maybe he will have no choice but to use his blood if she's dying? If she's going to die anyway, then it's worth trying. 

Or we can go another route and completely split them up for a small stint due to his family's threats etc and that she isn't good enough as a human. Then enter Clan Moncourier! Her mother's former lover was a possessive vampire (she found out too late who he really was) and she had a son by him. She was then rescued by Alex as the other vampire was left with the baby. So Victoria has an older half brother and an attachment to a powerful French vampire clan, who will protect her and they could even still practice the ancient ritual and turn her. So she could return to the Hygraces as a fully fledged vampire one day and prove them she is worthy (if Vail hasn't severed his attachment and married Sylvia yet).