I have some suggestions:
armour:
spiked armour (when hit 20% of the damage taken is reflected back onto the enemy who hit the soldier that had the spiked armour and it only works with melee)
slanted armour (deflects all projectiles except for bullets)
traps:
spike pit (a pit that has spikes at the bottom)
poison trap (shoots a poison arrow when the trip wire is activated)
fire pit (a pit with fire at the bottom)
units:
armoured archers/crossbows
armoured riders
armoured elephants
camals
armoured camals
hoplites
pikemen
assassin (a quick hitting unit that has 2 blades and moves quick)
poison hwacha
that's all I can think of.also I was looking at other comments and some were talking about a modern one.will you still continue updating this when the modern one comes out?and also I have a 4 gig laptop and this game runs very well on it and I think this game is awesome.thankyou for reading all of this.