Thank you very much!
Regarding first point, I think enemy drops lost during slam attacks ending up back in the stack would be a bit confusing and quite overpowered. However, bosses already do drop their item even if they're killed by a move action (the item is dropped in previous player position), so don't worry about bodying them if you have to!
I agree that perk system really needs some spicing up and upgrades would be one way to go about it. And the game also already has more neutral perks implemented, I just haven't found a good-enough way to grant them to players. Some might be game-breakingly OP, but there's a bit of fun in that also :)
Healing slimes sounds hilarious! Would be hard to explain it visually, but it seems like a fun and weird mechanic to have. Other ideas are also interesting, I especially like the burning enemies to drop scrap or stun enemies on attack. These really fit the game well and wouldn't be hard to add or visualize!