I feel you're missing the point, so let me try and clarify it one more time. What is the point of being Vampire A (Vanilla Vampires), when you can be Vampire B (Vampire Lords), which has all the same weaknesses, bonuses, and abilities as Vampire A, but also has access to another form that Vampire A does not have?
Would it not make more sense instead to simply introduce a new group of vampires that are radically different than the previous vampires, so that you chose the strain that best fit your playstyle, rather than getting the same basic thing, but with one new perk added to it?
That's the redundancy. There is nothing gameplay wise that makes playing as the original vampires appealing, because you can easily become a Vampire Lord instead, and have all the same powers as your vanilla counterparts, as well as a whole heap of new abilities that the vanilla strain can't use.
Don't try and use story contrivances on this. We're purely talking about gameplay here. What do the vanilla vampires have that could persuade players to choose them rather than Vampire Lords? If they don't have anything to make you want to play as them rather than the new breed, what is their point from a gameplay perspective?