New Units/Building- Mercenaries
I think a cool edition to clash of clans would be mercenaries. After all the Dark Troops are done they should make a building called the Hiring Station. You Can get the Hiring Station at Town Hall 10 and it costs,1MIL Gold. In the Hiring Station you can hire mercenaries which cost gold to get. Some units could be.
Bandits- Bandits are the unit you get when you first construct the building they target anything but do more damage to gold collectors and storages.
Duelist- the Duelist is unlocked at lvl 2 Hiring Station and take 3 powerful shots with their Flintlock Pistol then use a Dueling Sword to attack, they do more damage when fighting clan castle troops.
Knight- a Armored and version of the Hog Rider this guy does a decent amount of damage and a lot of health and can also move fast because of his horse and jump walls I am not sure about what lvl you can unlock This guy at.
Black Knight- This Guy will be the final unlocked guy. He acts like a barbarian king he can jump walls and he's huge he does massive damage and has a lot of health, BUT he is very very slow so you need to make sure that defenses can get him before he destroys your base.
Well ill this is my idea that's only 4 out of 12 units so anyone who is reading this and has a idea say down below and hope that supercell adds it in