Wedge formation

[caravel]

I pretty much only use it for throw away units such as Ghazi Infantry. They can be launched from ambush in wedge formation and deal some horrific damage. I will never use it for a faction leader's, heir's or general's unit or for a unit containing a valuable unit leader as it places him at the point of the formation where he is often the first to die. I must admit that I do also use it for maneouvring horse archers, and sometimes other units, out of tight spots.

[Roark]

I use wedge with lance/spear cavalry and fast or high attack+charge infantry against thinly deployed enemy units.

If you can split the formation, the unit will rout a lot quicker.