The big question, from both a mechanics and flavor perspective, is
what do vampires do? - Fangs, which like most flavor mutations work pretty well
- Bat transformation, which complements the hexer gameplay style by providing a needed escape mechanism
- Blood drinking, which is a fundamental part of vampire lore but is poorly implemented even by hunger mechanic standards
- Transformation between living and dead based on satiation, which from a gameplay standpoint requires constant micromanagement of fiddly hunger mechanics for entirely situational benefits (resists) and is more associated with The Elder Scrolls 4 than general vampire lore
- Stealth
- Enchanting
In lore vampires tend to have superhuman strength, resiliency, and regeneration, although Vp doesn't do anything with this beyond some extra regeneration when full.
Some other aspects of vampire lore that would make good crawl mechanics are already taken by other species/gods
- Darkness, jumping out of the shadows, turning into a mist (Dithmenos)
- Lifestealing (done better by Mahkleb, Vine Stalker, and to some extent Ghoul)
- Neither alive nor dead (Gargoyle)
- Forsaken by god (Demigod)
- Shooting fireballs (every race that doesn't have -3/-2 conj/fire)
- Wealth (Gozag)
The most pressing issue for the species is the hunger/satiation mechanic. Reducing it to two states is better but it's still a band-aid on a broken system that dominates the species experience without adding interesting gameplay. It might be most convenient to treat vampire as a typical chunk eating species that, like a gargoyle, is neither alive nor dead.
- Code:
Vampire
Same stats (7s/10i/9d) and growth (+1 dex or int every 5 levels)
SInv
Fangs 2
HP regeneration on stabs
rPois, rC+, rN+, and partial torment resistance (same as gargoyle's)
+50 stealth
Can't worship good gods or Fedhas or wield holy wrath
Vulnerable to holy wrath and dispel undead
Can't cast revivification, ddoor, or necromutation
Vulnerable to rot and mutation
Can berserk and transmute
Same MR/level (+4)
Bat form at level 3
Fangs 3 at level 7
Regen+ at level 13
Same apts except Tloc is changed from -2 to 0 (why is it restricted in the first place?)
It mostly merges the benefits of being full and being thirsty, so it might require a slight nerf. The idea is to keep vampire in the role of the game's default hexer, keeping the high aptitudes for hexes, stealth, and short blades and (similar to Mf) bad aptitudes for armour and conjurations which prevent going full melee or full caster. They're kind of like spriggan-lite in that bat form allows them to escape if they get unlucky and confusion fails 5 times in a row, but the escape button doesn't fundamentally alter how the species plays.
I had another idea based around a bloodlust drawback sort of like a mesmerization that applies to every monster on the screen but there are a lot more complications to that then fitting vampire as the basic hexer.