Cross-posting my most recent Steam post here in case people don't watch those forums:
I think that the molotov cocktail is a super underrated weapon. That being said, I can think of three similar weapons that I think would be excellent additions to the series.
1. acid flask. works exactly as a petrol bomb, except it keeps burning through terrain round by round until it reaches the water at bottom. (burn rate would be fairly quick vs. petrol)
2. arcane/magic fire - works exactly as a petrol bomb, except the fire is purple and never burns out. (but is editable of course... if we could edit the petrol bomb in such a way, this weapon would be redundant aside from the cool purple fire)
3. wrinkle cream - lol, I know the name is weird but picture this: you throw it just like a petrol bomb and it basically just splashes out and adds to the terrain wherever it touches. you could throw it and fill in holes to prevent people from getting to use (instead of wasting a precious girder), or you could encapsulate another worm and force them to dig out, burrow, or teleport. I think it'd be a great defensive weapon.
Now that I think about it, we should definitely be able to set how many rounds fire/acid last. Being able to edit the "burn rate" of the acid would be great as well. Just some late night thoughts...
I also think that the fire created by exploding crates or barrels should last longer, and be editable. I personally would like to try playing a scheme in which fires NEVER go out, and in fact they can spread on turns with wind above a certain strength. ALSO, fire should still burn through terrain. More slowly than acid, but it should still burn rather than just sit on top of it and do basically nothing like it did in the 2.5D games.
It would also be cool if smoke from fires could make smoke screens in which nobody can see into it or out of it, "fog of war" style. Optional, of course.