Lately I've been reading "Greek Fire, Poison Arrows & Scorpion Bombs: Biological and Chemical Warfare in the Ancient World" which leads me to the conclusion that there is not enough poison in my D&D games.
Poison traps and poisonous bites of monsters sure, but they tend to be immediate "Save or Die" situations more than anything. Spells of Neutralize and Slow Poison exist, and should be resources to expend, and I should structure poisonous threats to generate more building debilitation or death after hours. Provide anti-venom or potions as resources to be purchased and expended, and accentuate the decision to press on or return to town rather than rolling up a new character.
Poisons in 5E are on the right track, though the PHB item is a little too expensive for the minimal effect, but I like to see it tied in to the proficiency of the character and some resource management. The AD&D PHB mentions belladonna and wolfsbane with little mention of their use. I'll have to dig out the Dragon Magazine articles expanding on the AD&D DMG to provide the variety and background of knowledge. I've never found the exact fit for effective spell component use vs recording keeping headaches, and maybe poison creation (especially with recipe elements like Skyrim or Dragon Age video games) can be a test run of a better method. I'd like to see thieves, assassins, and alchemists concocting their poisons and others buying them, and actively using in combat (or sneak attacks).
I love a good backstab and don't want that to disappear, but thugs with envenomed daggers fit better than gymnastics amid a melee. Thieves get a resource to be managed, to improve combat damage or eliminate foes. Certainly one that fits my vision more than some of the "combat effectiveness" abilities presented in various rulesets.
War Pigs, or at least war dogs (guard dogs in AD&D, mastiffs in 5E, I presume), always seemed to be a crutch for low-level characters in my younger days. They were set aside after a couple leveles, and took the place of some hirelings. Still, I like the idea of the baggage train expedition. If war animals or military elements don't work for you in the dungeon, they work at camp to guard the horses, or assist with the party's night watch. They require a hireling the manage more than one, and best yet - require no share of treasure beyond some iron dog chow.