My idea is that we should have some options to place traps on the battlefield(field prep where you might have line of pointed stakes placed close together and disguised at a bottom of a pit) or some flammable liquid as in Braveheart.  I think there should be both mechanical and magical traps.  I think very few battles are truly of the ambush variety.  Most battles the opposing armies know who they are fighting and roughly where and when.  They have time to set up field fortifications, formations, logistic routes and caravans, and scout out the opposing side.   

  I would like to place various traps around my Kingdom.  I realize we don't want every faction to have access to the same technologies.  Maybe, have 2-3 factions that have signigicant trap utilization skills. 

  Mechanical Traps-

Caltrops for quick defense before imminent attack or to delay forces.

Disguised or hidden pool or pits of stakes, acid, boiling oil, pitch and tar, hungry animals, etc.

Moats filled with burning oil or dangerous creatures.

  Magical Traps-

  A spell that allowed me to Ward an area with a Glyph or Rune.  Whenever area is approached the enchantment takes effect and results in a audible glamour effect.  Mysterious colours and lights flash with strange noises.  If the area is advanced upon then a resulting explosion doing X amount of damage in area of effect.

  A misdirection effect.  Units become lost or confused.

  A web on the units.

  Would be nice if we have the ability to control where these traps were placed.  Some quests should also have traps as part of the adventure.  If this topic is already discussed and done I apologize and please redirect me.