sort of silly to say that an archer can shoot through a square but not at a target in that same square.  shortening the range of bows would be a lot more realistic and just as effective.  (the archers would lose the same number of effective squares)  giving melee units greater mobility would be equally effective.

not that i agree it should be changed, just that it makes more sense.  I like archers as they are, simply because there is no other way to deal with creatures with 150 attack other than using children. 

I wouldn't really consider bows overpowered when the basic armor tech can render them nearly entirely ineffective.

Archer units need;

1. Opportunity Fire - option to automatically attack first unit that moves into range.

2. 2nd Attack Delay - i.e. archers attack, enemy moves, archers attack again.

3. Crossbows - one attack per turn, Units with crossbows can be trained faster

Defenders need;

Tactical Spell (air) - Wind Wall - Reduces range of all archer units on the map

Tactical Spell (fire) - Smoke - Reduces attack range for targeted units to 1, due to smoke interfering with vision

Battle Formation Order - Shield Wall - +4 Defense Bonus vs Archer Attacks/-1 movement - A unit equipped with shields can be ordered to assume a shield wall.