How about -1 for attackers in melee on all to hit rolls only and +1 for defenders to hit rolls only.
Range modifier of +3 inches per level of hill for missile troops with ability to shoot over own troops. range reduction of -3 inches when shooting uphill. What think???
There are already allowances for this in the game system, the attacking unit will receive a -1 to its to hit rolls as it will either count as a disrupted charge on the part of the attackers or that the defenders are in a defensive position.
Was thinking of speaking about cost of magic items as well as only being able to have one artifact type on battle field notably missile weapons i.e. only one unit may be equipped with piercing arrows in the army or brew of haste --- would like to propose that if you equip a unit with magics the cost is for every 10 (ten) models (if INFANTRY), or 5 (five) models (if CAVALRY) with NO restriction on how many times it can be copied in the army building phase.
EXAMPLES --- 2 regiments of "Ironwatch" Dwarves could both be fielded with "piercing arrows" at an additional cost of +10 points per unit --(140 points each)-- COST = unit points cost (130 points) + 2 X COST OF ITEM (5 points) (20 FIGURES IN UNIT) = 140 points each
The following rule would apply for max number of items per unit
1) HEROES --- max of 4 (four) items:
2) INFANTRY up to 10 figures --- 1 item:
3) INFANTRY 11-20 figures & CAVALRY up to 5 figures --- 2 items:
4) INFANTRY 21-30 figures & CAVALRY up to 10 figures --- 3 items and
5) INFANTRY 31+ figures & CAVALRY 10+ figures --- 4 items
No offence but this is yet another glorious example that people who haven't read the rules or played the game yet should NOT!!!!!! make suggestions for in house rules because the have absolutely no clue what they are talking about. Every single thing you've said about magical items is completely irrelevant because it already states in the KOW rules that:
"Each unit can have a single artefact chosen from the list below, which is
normally carried by the unit’s Leader. The cost of
the artefact is added to that of the unit.
Unless the artefact specifies otherwise, the
following limits also apply:
• Each artefact is unique and therefore can
only be chosen once per army.
• War Engine units cannot choose artefacts.
• Monster units cannot choose artefacts (but
Hero units definitely can).
• Living Legends (i.e. units with a  limit)
cannot choose artefacts."
This was taken from KOW rulebook page44 and is also on page 23 of the free download basic rules on the Mantic site.
so for god sake people can we all actually have a proper read at the rules before we start posting suggested rules changes or "in house rules" because i really like this game and i don't want it to go the way the AT-43 campaigns went.
but a wee bit of complexity often helps
The final thing I wanted to say is that KOW IS a simple system and that's what's good about it. If you want a system that's more complex do what Walter's done and get an army for Warhammer Fantasy
Rant Over, For Now