Thank you to all those who have been participating in this conversation, and for providing your perspectives on this matter.
I appreciate your contributions, and shall attempt to summarize and address the discussion so far.
- Diseases are fairly trivial to remove: take-20 on heal-kit plus just general Heal modifiers overcomes even maximum DC 30 at low levels.
- Heal-kits do not respect Extraordinary (mundane) vs Supernatural (magical) diseases, despite listings in the 2das.
- Incubation time for Diseases is impractically long for many circumstances, given the availability and immediacy of counters.
- Diseases have meaningful and potentially significant effect at low levels when not countered, but appear to diminish in potency as level increases.
Having run some experiments and done further poking about, I have also confirmed some other properties:
- Contagion and Mass Contagion not follow SRD. Per SRD, both should apply their disease "which strikes immediately (no incubation period)". This is unlisted in the NWN2 spell, which does not (so it takes 15 minutes/rest to actually kick in).
- Contagion forces a Fort Save vs Disease, with no Spellcraft save bonus. Mass Contagion forces a Fort Save vs Disease, but does benefit from Spellcraft to saves. At least one of these is wrong, and it's probably the one that has the less save bonuses, further emphasizing just how poor these spells are vs high levels (where a target is likely to either have inflated fort saves, or a hefty bonus from Spellcraft. Or both).
- Heal Kits are tested against the DC of the disease or spell. For most environmental diseases, that ranges from 12 to 18. For Spells, they appear to suffer from the same table problem as Poison, with a fixed result per DC, to a max of DC 30, where higher DC effects can have mechanically worse utility (DC30 Demon_Fever3 is strictly inferior to DC29 Ghoul_Rot which does the same 2d6 Con plus an extra 1d4 Str, and quite a few lower DC diseases).
- Disease damage was determined to stack over multiple rests - if the target failed to succeed multiple saves in a row, with 24-hour/rest between them. This clearly affects lower levels who can rest more frequently and fail the save, than it does higher levels who will pass the save and can't rest more than once every half hour at best - if they don't just remove it outright in the course of standard play with the tools available (like pockets full of Potions of Heal).
From these observations, it seems fairly evident that the risks are concentrated to lower levels without saves and resources, and trivial to those higher. Some changes could be made that are simply practical, others more divergent implementations that serve to give more thought to the mechanic. With that said, here are my suggestions for consideration, collectively or seperately as may be:
- Apply Contagion/Mass Contagion immediately, with no incubation. This is the P&P implementation, and makes it so the spell actually has shorter-term use, rather than "Cast and hang around for half an hour until the target takes a minor stat penalty". Why NWN2 decided it should take 2 minutes (in Vanilla) and 2 failed hopefully DC 16 fort saves for a P&P combat-spell to work and deal *checks table* 1d6 stat damage maybe, I have no idea.
- Heal-Kits to remove Disease are against double the DC of the disease. This would put a DC 12 save up to a DC 24 heal check - still doable with an out-of-combat Automatic-20 even by a level 1 trained in such things, but makes it less trivial to simply Heal-Kit off a DC 30 Demon Fever from a high level caster (at Heal DC 60), and would give serious consideration to use of Cure Disease (or Heal, or Greater Restoration).
- Consider prevent Healing Kits from curing Supernatural diseases. In P&P this applies almost exclusively to Mummy Rot which has the ruling:
Successful saves do not allow the character to recover. Only magical healing can save the character.
However, Healing Kits are already incredibly powerful simply from their curative power, eithout taking poisons and diseases into trivial account. Making supernatural problems require supernatural solutions is at least thematically consistent.
- Consider adding a Caster-Level check for removing Supernatural diseases. Per the text for Remove Disease:
"Certain special diseases may not be countered by this spell or may be countered only by a caster of a certain level or higher."
- Prevent use of Healing Kits to cure Diseases entirely. Instead, during the Disease Payload step during rest, have the party member with the highest Heal skill roll, and use whichever result is better. This would be effectively the implementation if P&P "Healing a Disease" which states:
Healing A Disease
Use of the Heal skill can help a diseased character. Every time a diseased character makes a saving throw against disease effects, the healer makes a check. The diseased character can use the healer’s result in place of his saving throw if the Heal check result is higher. The diseased character must be in the healer’s care and must have spent the previous 8 hours resting.
By removing the ability for Heal kits to instantly cure Diseases, it actually gives them a chance to work over time, can still be cured away with magic or healer-characters, and gives some meaning to their honestly pitiful stat damage. Or gives people a chance to start adding a Lesser Restoration Potion in their morning coffee, I suppose.
- Hide the Disease VFX until after the incubation period has passed and at least 1 save has failed. By nature of how a disease works, there usually are no symptoms visible for a while after the initial infection event - which is what the incubation period is (finding a modern example would not be difficult). Not being an immediate GIANT WOOBLY GREEN CLOUD despite having no actual stat damage would certainly help immersion, as well as be reflective of when damage (and thus visible symptoms) were actually applied.
- Consider reducing the incubation-time to combat-relevant levels (such as a 1-minute incubation down from 15). This is almost counter to some of the suggestions above but would result in more combat-useful diseases, rather than longer narrative impacts.
My personal preference would be implementation of #1, 2, 4, 5, and 6 in the list above.
This combination would make Diseases more of an ambient concern without increasing severity, but making them much hardier and a longer process to remove without magical aid. Risk at low levels would not actually increase due to the higher rate of Rests that already made it more impactful, while at higher levels the longer rest delay and hardiness to trivialization would give the diseases more narrative impact - even as they can still be overcome with plentiful magical resources or skills/saves.
If events were to occur that complicate access to divine magic, these narrative impacts would likely have greater weight.
Some considerations of tweaks to disease variety and DCs at higher levels could also be considered, as could the (Mass)Contagion (and Poison) list and implementation, but would be a separate considerations from actual Disease mechanics.
Suggestion #3 to me seems heavy handed, and penalizes a valid use for a skill that simply wasn't implemented correctly, and that #6 is a far better solution than making the rule of one disease apply to an entire collection.
Suggestion #7 is listed as an option, but basically turns Diseases into Poisons, which I see as a mechanically and thematically distinct set of effects. Where a poison is intended to debilitate immediately and severely (and thus ideally combat useful), a disease debilitates more persistently over time but at a lower severity.
As ever, commentary, concerns, and query is welcome.
Cheers,
Kit.
