I really think powder needs more features instead of elements and walls.
1. Sound.
Like you can hear wood burning, the bigger the flame, they more intense the fire, and a sound for explosions.
2. Physics.
Add a feature so that you can un-freeze solids, so you can attack ropes to them and hold them over fires and things. Would be fun to have a fireball smash into a city and destroy it.
3. WWMD ffsafsa whatever its called.
So when there is an explosion, Break into shards of metal instead of dust.