I know, right? and you could just see it - floating with its toes just above the ground like the ossiarch soulreaper, tattered robes over it's lower half, bare chested with a scalloped cape and high collar on the upper half to show off its withered, emaciated form and necrarch style face, clawed hands raised in arcane gestures with spirit energy swirling about like GW likes to do with wizard models sometimes. rules-wise it's also pretty straight forward - vampire lord with one less save, one less attack, no command ability, but two casts/unbinds and some kind of cool signature spell, maybe old style vile transference, maybe just give it the same spell that the vampire lord lost.
Necrarch-style bloodline also practically writes itself, revolving around a core dynasty feature of letting their vampires choose spells from the deathmage lore. Maybe a 'vampiric magic' ability that lets your vampire wizards drain one wound from enemy wizards whenever they unbind an enemy wizard's spell, or whenever an enemy wizard tries but fails to unbind one of theirs. Throw in some caster oriented command traits and artefacts, some others that support summonable units, to nudge the subfaction's list building away from the more jockish vampire units, and you're good to go.
As is, I guess vyrkos is what we've currently got for a 'magic bloodline', but while the theming isn't exactly /not/ there, I mean there a certain baba yaga / witch of the woods feel that sort of fits their russian forest kind of flavor, but it's no where near as direct as the old necrarchs or the legion of sacrament were, and while Volga herself is an impressive spellcaster, the generic vyrkos vampires are held back by their lack of signature spells and the overall badness of the vampire spell lore.
It really does leave a pretty obvious and painful thematic gap in the faction where a necrarch dynasty, or a non-vampire deathmage dynasty, or even a 'these are historic rules' legion of sacrament dynasty wants to go. Hopefully that gap is obvious enough to the designers that it gets filled in later. In the mean time there's always home brew.