Dark Elixar Upgrade to Standard Troops
Firstly, there needs to be a threshold level on where this upgrade can be applied, say town hall 8/ level 5 troops.
The idea:
Take archers. With this dark elixar upgrade archers would gain the use of fire arrows. These arrows would shoot the same as ordinary archers but with the advantage that when the buildings are hit they "get set on fire" and incur additional, but reduced damage over time, say 5secs after the last arrow has hit the building. So when attacking a building and you are on 99% and your troops die, the use of fire arrows could then mean the last building would fall due to the fire damage. Woohoo 100%!
There would be an upgrade cost to gain the use of the fire arrows in the first place per say, 10,000 dark elixar and then additional cost of say 5 dark elixar per archer. However, no dark elixar? Fear not. The archers will be used as normal without the use of the dark elixar. In a similar style to inferno towers, the troops could be bought this special ammo.
Similar mechanics could be applied to a variety of troops:
Barbs - fire blade
Wizzards - fire bolt
Dragons - fire breath could actually be fire!
Wall breakers - fire spreads through nearby walls on explosion
The idea could be furthered for most troops.
I apologise if this or a similar idea has been brought up before but its new to me.
Thanks!