Critical strikes now implemented as stacking bonus damage rather than double damage

Replace "crit chance" with "accuracy".

Instead of having a 0-100% chance of doing 100% additional damage on a crit, you apply a stacking mark that causes your auto attacks to do 0-30% additional damage (based on how much accuracy you have, the number 30 is subject to change) to the target on any subsequent hit. The marks can stack without limit, but they disappear if you have not damaged the afflicted target with an auto attack within the past 4 seconds.

Here is the amount of damage dealt per auto attack in terms of the attacker's total attack damage, as a function of the number of attacks made against that particular target so far, with 100% crit chance and 100% accuracy. The red line is the current scheme where the total damage per auto attack is always 2x the ad of the attacker. The proposed scheme starts at 1, then increases to 1.3, then 1.6, then 1.9 etc.

Y = Damage each auto does (in terms of the total ad of the attacker) X = number of attacks made against that target prior to this attack http://imgur.com/kUeHaoZ

This is the graph of the sum of the amount of damage dealt over all attacks combined together, in terms of the attacks total attack damage, as a function of the number of attacks made.

Y = total damage dealt so far (in terms of the total ad of the attacker) X = number of attacks made against that target prior to this attack http://imgur.com/lYdNTgu

The motivation for this change is simple:

Random based critical strikes are unpredictable and with significant amounts of crit chance they do not create choices. With low amounts of crit chance they subvert the premise that interaction between players fundamentally ought to be based on decisions that the players make.

The suggested "accuracy" based critical strike system is not unpredictable and creates choices. The choice is either remaining in combat and withstanding the additional damage per auto attack or to disengage from or drive away the attacker so that the mark falls off after 4 seconds. It discourages long fights and encourages short skirmishes as a counter play against someone who has a lot of "accuracy". This new impetus for aggro cycling in team fights creates a more dynamic team fight experience.

It also provides an opportunity to create more interesting item and skill designs that interact with critical strike, like spreading or moving the marks from one target to another or removing some of the marks for meeting a condition, or instantly adding a certain number of marks to a target if you land a skill shot or etc. In other words its richer as a system than the current incarnation of critical strikes is.