This is a bit controversial, on one hand I'd enjoy a better SR drop, on the other hand I think druid NB is already by far the best SR drop around and balancing mobs around its aoe -16/17 drop (when the best alternatives are single target -10/12/14 ones, and the latter requires a psf abj arcane using a lvl9 slot) would make the class even more required than it is now.
I think a more interesting concept would be a torch (for bard/mage/cleric) actually increasing the SR drop of bestow curse (by 3 points I'd say, for -15 drop max, ''almost'' druid level); your defences take a big hit but, paired with
Visor of Cursed Chaos, you could act in emergency as a druid-substitute, at least for the SR drop, while still not stealing their job(s).
Also, there're not many viable torches for casters
So... to hijack this a bit...
Paragon Set Loot:
Beshaba's Kiss
Base Item: Torch
Weight: 5.0
Special Properties:
+18 Armour Bonus //deflection, cosmetic
Bonus Spell Slot: Wizard Level 4 //mid level slots to actually have lot of room for Bestow Curse, even at various metamagic tiers
Bonus Spell Slot: Wizard Level 4
Bonus Spell Slot: Wizard Level 4
Bonus Spell Slot: Wizard Level 4
Bonus Spell Slot: Wizard Level 5
Bonus Spell Slot: Wizard Level 5
Bonus Spell Slot: Wizard Level 5
Bonus Spell Slot: Wizard Level 5
Bonus Spell Slot: Wizard Level 6
Bonus Spell Slot: Wizard Level 6
Bonus Spell Slot: Wizard Level 6
Bonus Spell Slot: Wizard Level 6
Damage Immunity: Divine 5% //there're already many phisical% and elemental% options
Damage Immunity: Magic 5%
Damage Immunity: Negative 5%
Damage Immunity: Positive 5%
Damage Immunity: Anarchic 5% //not a single XR torch gives esoteric imm, this is little but every bit helps
Damage Immunity: Axiomatic 5%
Damage Immunity: Ectoplasmatic 5%
Damage Immunity: Primal 5%
Damage Immunity: Psionic 5%
Damage Immunity: Sacred 5%
Damage Immunity: Vile 5%
Immunity: Charmed //I honestly do not know if it's becoming a useful property, mostly cosmetic given item background
Immunity: Daze //QoL immunity and fitting, not present on any XR torch.
Skill Bonus: Discipline +15
Skill Bonus: Lore +15
Skill Bonus: Persuade +15
Spell Immunity: Bestow Curse //makes sense
Only Usable By: Bard
Only Usable By: Cleric
Only Usable By: Sorceror
Only Usable By: Wizard
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Wearing this item will cause Bestow Curse to drop SR by 3 more than usual
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Using the unique power on this item will toggle its spell slots between various spellcasting classes //bard,cleric,sorceror,wizard; BG could cast BC too but I can't really imagine a casting version for those
You lose a lot of armor class but could also swap it on demand (in that case, bards-sorcs might want to select the spellslots for another class, in order not to lose spells every time); still a big sacrifice in immunities compared to alternatives but very welcome in druid-less parties.
Should be considered a improvement to
BUR caster torches imm-wise but the real competitors for the slot are asmo/caster shields like a slots-auged
UR-Ward. It might give new life to monk-splashed bards, who knows.