Die Spectacularly - Troop Death

I was watching an attack with balloons attacking a base and when they go down, a kind of small explosion happened but no damage occurred. Also, as dark elixir is "really volatile" and stuff, I was thinking that when some troops die, they should go with an explosion, which could do 5hp damage in the surrounding 2 tiles (obviously, subject to change). This is the table I came up with.
DE Troops: Unlocks at Lvl1, increase in damage/range when upgraded
Barb: Unlocks at Lvl5, increase in damage/range when upgraded
Archer:Unlocks at Lvl4, increase in damage/range when upgraded
Goblin: Unlocks at Lvl6, increase in damage/range when upgraded
Giant: Unlocks at Lvl3, increase in damage/range when upgraded
Wall Breaker: Cannot Unlock
Balloon: Unlocks at Lvl3, increase in damage/range when upgraded
Wizard: Unlocks at Lvl2, increase in damage/range when upgraded
Healer: Cannot Unlock
Dragon: Unlocks at Lvl1, increase in damage/range when upgraded
P.E.K.K.A: Unlocks at Lvl1, increase in damage/range when upgraded

The action would be similar to when a balloon goes down, and it wouldn't do too much damage so there isn't a possibility of it becoming too overpowered. Let me know what you think!