The title flags two of my biggest gripes about the game.
If I had enemies using the level of AOE grenade attacks as this game does, I'd be running TPK campaigns consistently. Goblins especially shouldn't be using grenades. Numbers alone are bad enough. The fact this is the way the game is currently leaves me using cheese combat tactics like staying ranged and shooting out a door and then closing it for each player.
Environmental effects and interactions:
There are too many things that will chain an entire map to explode at once. The notable ones are in the Zent hideout and the goblin base where the halfling trader is. The Zent hideout was exceptionally bad. I was playing a beastmaster ranger with a spider (please fix bear pet's hp btw). The spider shot a web attack at an enemy in there and it clipped a fire. That fire then set the web on fire which then proceeded to set the entire cavern on fire as things exploded in a massive chain reaction. Acid is another problem. It just never goes away. Cantrips aren't supposed to create permanent hazards.