Condensing all of NetHack’s poison mechanics into one unified mechanic:

• Dexterity and Constitution poisons are removed. Quasits (the only AD_DRDX attack) might still directly harm Dex, but it’s no longer flavored as poison. Rabid rats (the only AD_DRCO attack) don’t cause poison, they cause disease, which hits Constitution. Poison will now only affect Strength.
• Poison is now implemented as a timing-out trinsic. The amount of Str loss is a direct function of how much timeout is left, so Str will gradually recover as the poison goes away.
• Passing Con saving throws could give small bonuses to decreasing the timeout faster than normal.
• While poisoned, HP regeneration is either impeded or stopped entirely, or else the player’s HP is damaged every turn, or every several turns.
• It could also heavily abuse Str while it lasted instead of being directly tied to Str.