Sabbat games of Vampire: The Masquerade have a lot in common with Werewolf: The Apocalypse in terms of pack structure and rituals, an overarching supernatural enemy and so on - all the things that make them harder to explain than Camarilla or Anarch games - so it occurs to me that this could also solve the other common problem I have with Sabbat games, that they focus on attacking Camarilla vampires and general chaotic rampages.
Give the Antediluvians servants to oppose, cults like the Black Hand and weird not-quite vampire things, as well as Noddist secrets to pursue and night-to-night vampire problems to approach in a different way.
One tricky part is that the creepy body-warping horrors of the setting are on the Sabbat side, which would make the enemy different from the Wyrmspawn. (The Tzimisce, providers of most of the weird monsters in the VTM computer games. I’d happily drop them or nudge them onto the NPC side, but hey... Of course, I could follow some of the setting secrets and have Tzimisce active and working against the Sabbat’s supposed purpose.)
So... hmm... ancient revenants, so old that they can make ghouls themselves?