1) complete re-think of the lore of the vampires. The new concept is "the vampire wizard draws blood from an enemy unit, and uses that blood to empower themselves or other vampires". In practice this means all of the vampire spells are both minor magic missiles - 1 mortal wound at 18" range, or d3 mortal wounds if cast with an unmodified roll of 9+ (replacing the double-cast). Then the follow up effects could include things like "the caster may immediately pile in and attack as though it were the combat phase, but afterwords strikes last in combat until the end of the turn", "the caster gains +6" move in the following movement phase", "choose a vampire unit within 12" of the target and heal up to 3 wounds allocated to that unit", "choose a vampire unit within 12" of the target, the chosen unit gains +1 to ward saves until the start of your next hero phase", "The vampire may immediately cast an additional spell they know, with a +1 bonus to the casting roll. This does not count against the normal limit of spells they can attempt to cast" - stuff like that. Gives the whole thing a 'blood magic' feel.
2) Significant rework of the subfactions. Fewer command traits and artefacts - 3 per subfaction instead of 6, but with serious effort put into making all of them good. Each subfaction also gains their own set of three 'bloodline traits' as a unique enhancement. Every non-unique vampire hero gains a bloodline trait, and you are allowed to take duplicates of the same trait if you wish.
2a) Legion of Night: lose outflank, lose battleline vargheists, become the deathmage faction, highlighting Mannfred's mastery of necromancy. Lore-wise add new fluff that Manny specifically went out of his way to find and recruit scattered survivors of the Legion of Sacrament, and that in doing so he's learned many of Arkhan's & Nagash's secret rites and plans. LoN gains +1 to cast deathmage spells, mannfred knows all of the deathmage spells. Bloodline traits: 1) Necromantic Study (wizard only) vampire may choose their bonus spell from the deathmage lore instead of the vampire lore. 2) Grave Walker (<10 wounds only) Vampire may deploy 'in the grave' as per summonable units. 3) Shroud of Darkness: -1 to hit for shooting attacks directed at friendly units wholly within 12" of the vampire.
2b) Vyrkos Dynasty: lose their current faction traits. Gain the outflanking trait that Legion of the night lost, which imo better fits a hunting wolf pack than their current rules. Lore-wise say that since the destruction of Ulfenkarn and the quiteting of the necroquake most of the bloodline have abandoned pretentions of nobility and returned to skulking the hinterlands of shyish, as they did throughout the age of chaos. Bloodline Traits: 1) Wolf Aspect - can retreat and still charge later in the same turn. 2) Bat aspect - at the end of your movement phase can remove them from the table and set them up again anywhere more than 9" from any opponent. 3) rat aspect (<10 wounds only) - the first time each game that this model is slain by wounds or mortal wounds caused by an enemy model, roll a die. on a 1-2 the model is slain as normal. on a 3+, remove all wounds that have been allocated to this model and disregard any remaining wounds or mortal wounds that have yet to be allocated to it. You may then immediately make a normal move of up to 12" as though it were the movement phase. You may make this move even if the model is currently within 3" of enemy models, but must end the move more than 3" from any enemy models.
2c) Legion of Blood: lose their current faction traits. Gain re-rolls for vampire casters. Lore wise not new development but retcon to go with the change to the lore of vampires - Neferata invented vampire blood magic, she is the master of it, and she shares her strength with her progeny. Bloodline traits: 1) quicksilver Blood - strikes first in combat, 2) Aura of Command - summonable units wholly within 12" gain +1 to wound, 3) Master of Intrigue - after deployment but before determining control of objectives, you may remove one friendly unit from the table for each vampire with this bloodline ability in your army. You may then immediately set those units up again, following the normal restrictions for deployment from the battle plan you're using.
3d) Avngorii: lose battleline zombie dragons & terrorgheists, gains battleline vargheists instead. The faction is about /becoming/ monsters, not animating their corpses. Bloodline traits: 1) Monstrous Form (<10 wounds only) - the vampire gains +1 wounds characteristic and the monster keyword, 2) ???, 3) ???
Haven't thought as much about what I'd do with the Avengorii & Kastelai.
4) Coven Throne is a buff wagon, but no longer a hero. IMO too much conceptual overlap with blood palanquin
5) in exchange, Mortis Engine is now a hero, deathmage, & dual caster wizard.
6) grave guard gain +1 save & a bodyguard rule for soublight heroes with <10 wounds
7) Black Knights gain +1 save & stronger lances to make them more of the medium cavalry unit, & leave fast chaff role to dire wolves and fell bats
8) Dire wolves cheaper, 1 wound each, making them chaffier, harder hitting for the points, & easier to heal, drop the bonus to hit and wound on the charge and give them retreat & charge instead.
9) Fell Bats: remove retreat and charge, gain deep strike.
10) Vargheists remove deep strike, gain 'the hunger', +1 attack, and 3d6" charge.
11) Vampire lords gain +1 rend and +2 attacks, VLoZD gain +1 rend on their sword attacks, +1 attacks with both sword and lance, Vengorian and Lauka Vai gain +1 rend, Vhordrai gains +1 attack with lance, Blood Knights gain +1 rend on the charge, etc. Most vamp melee heroes and units gain +1 attack or +1 rend or both.
12) Wight kings lose their command ability, gain +1 wound, can issue a command ability to a deathrattle unit once per player turn without spending a command point, when you activate a wight king in combat you may immediately activate a deathrattle summonable unit within 3", reduce in points.
13) simplified invocation. All heroes invoke once, healing 3 wounds or restoring 3 wounds worth of slain models to any friendly summonable unit within 12". If the chosen unit has already been invoked this turn, then heal 1 wound or restore 1 wound worth of slain models instead. Mortarchs Invoke twice instead of once. Soublight generals may choose to measure range for their invocations from gravesites instead of their own bases.
14) ditch the healing spell, not needed with better invocations.
15) no conditions on 6+ death ward.
16) Endless Legions: I constantly flip flop on whether to simplify it or remove it completely, replacing it with grave-digger-esque rules elsewhere in the book (maybe wight kings grave dig for deathrattle units, maybe various subfaction artefacts or command abilities summon or grave dig for specific units associated with them, etc).
17) Standardize 'the hunger' rule.
Changes to the unit line up, some of which requiring changes to the model range, mostly serving to retire the cursed city box set and retire redundant units
1) Vampire Lord on Barded Nightmare - new model, new unit, designed to complement blood knights.
2) Vampire Mage, vampire offensive statline but only 3 attacks, -1 rend. unique blood magic rule lets them suffer a mortal wound to enhance their casting, arcane hunger rule restores wounds when they successfuly unbind spells or dispel endless spells - in addition to normal hunger. Dientallos is an alternate model for this, even if it's a different base size
3) Radukar the Wolf, Kritza, Annika, the new Vykos hero, and maybe Cado are all alternate models for the generic vampire lord unit, even though some of them have different base sizes.
4) Torgilius is an alternate model for the generic necromancer, even though he has a different base size.
5) The Exiled Dead are alternate models for deadwalker zombies, not their own unit
6) The Sepulchral Guard are alternate models for skeleton warriors, not their own unit
7) Re-cut Velmorn onto a separate sprue and release him as the new generic wight king on foot model. Watch Captain Halgrim is an alternate model for a Wight King, not his own unit.
8) Re-cut Gorslav onto a separate sprue, release as a new generic gravekeeper hero for any subfaction
9) New Zombie Ogor generic unit for any subfaction, kosargi become alternative models for these
10) Re-cut Vargskyr onto a separate sprue, release as a new generic unit for any subfaction
11) New models for grave guard. The Sons of Velmorn are alternate models for grave guard, not their own unit entry, even though one is on the wrong base size
12) Soulblight Bloodborn - new unit vampire infantry, 8 models on 32mm base including unit champ plus one beefy model on a 40mm base, rules based roughly on Askurgan Trueblades, though maybe without the specific ghurish focus on monster hunting. Askurgan Trueblades lose their unit entry and become alternate models for these, or just become the main models for these if new models can't be fit into the schedule. Vyrkos bloodborne lose their unit entry and become alternate models for these. The Crimson Court lose their unit entry and become alternate models for these.
13) New zombie dragon model, with variant builds for Vhordrai, Vampire Lord on Zombie Dragon, and unridden zombie dragon. No terrorgheist, that's not a soublight unit anymore, though it may still be taken as an ally. FEC in turn get a new terrorgheist model, but lose access to zombie dragons except as allies.
14) New black knight models. No longer dual kit with hexwraiths, which get their own new model kit.
"A note on base sizes: Games Workshop has published a wide variety of unique models for the soulblight gravelords over the years, and some of these have included unique base sizes. While the base size of currently available models are always the most official and up do date, you can always continue playing with your models using the bases they came packaged on in normal games. Official events and tournaments can of course set their own rules on how they want to handle this."
That kills 10 or 11 (depending on whether cado makes the cut) imo superfluous warscrolls outright without rendering any existing models technically unusable, while opening up Gravekeepers, Vargskyrs, and zombie ogors as units any subfaction can play with, and adding vampire mages and vampire cavalry lords to the pile as new options.