When I have archers/casters in an army, I always move them to the far rear of the map if I think it's going to be a protracted battle.

I think that to make tactical combat a bit less checkers-like, to focus less on troop movements which I would do the same every time and more on stuff that actually can change the dynamics of a battle, it would be nice to have at least a couple of options for troop placement when initiating a battle. It doesn't matter what to call them, but for lack of better titles I'll use these:

Conservative - place all troops as close to the rear edge of the map as possible.

Aggressive - mostly like it is by default now; place all troops more forward.

Customized - not too complex or specific (no specific tile placements), just a couple of basic options with how to place different kinds of troops in different general places on the battlefield. This could be where I might decide to place archers conservatively, warg riders aggressively, and my heros in back or in front depending on if I expect them to be in a support or melee role.