When I first started playing, I remember being intimidated by the apparent complexity of the charge rules. Looking back they're not actually that complex, but I still have some ideas for altering them.
When making a charge attack, add 1D6 to your damage roll for every 6" your unit moves that turn -- rounding down (a minifig which moved only 11" would still only get 1 extra damage D6). The original rules only allowed you to gain 1D6 damage max from a charge; this version means that most characters will still only get a +1D6 or +2D6 at most, but vehicles will get more, providing an incentive to build vehicles which can charge.
Only count movement that is in a straight line directly towards the target -- if a horseman moves 6", turns to face his target, and charges another 6" to hit him, he only gets 1D6 extra damage.
Minifigs trying to parry charge attacks get a -1 skill modifier, but a minifig who has just made a charge attack cannot parry enemy attacks for a full turn. (Optional rule: if the defender has a longer CC weapon than the attacker, he gets a free response attack as the attacker closes in.)
The 6" minimum means that a normal minifig can't usually charge, but unlike other attacks, you can make a charge attack on the same turn that you Sprint. (I decided on a 6" minimum to fix the main gameplay issue with the charge rules -- a minfig already in close combat can move away from his enemy and charge them again on the same turn.)
Optional rule: If a minifig fails to pierce his target's armor on a charge, he may choose to push his target back by a number of inches equal to the damage he rolled, as long as the target is no larger than the Charging unit.
TACTICAL NOTE: in infantry combat, these rules seem to favor large armies of cheap units, like zombies or Dimmies, with light CC weapons. Units composed of more skilled, better-equipped fighters will be more vulnerable if they charge themselves, but more capable of surviving a charge intact and striking back.
