[Sawrock]

In this proposed system, glancing blows only applies to basic attacks.
The three main stats used in these calculations is Defense, Resistance, and Celerity, along with the values on your torso equipment.
The equation for deciding if an attack is a glancing blow is in the original post, however the amount for determining the reduction of glancing blows differs. In addition, Glancing Blow's Reduction would be used instead of Defense, NOT STACKED WITH. The reasoning follows, as well as the equation. This is for physical damage on a glancing blow (most melee weapons, bows, etc):

DEF (max value of torso's armor value) + CEL (max value of torso's evade value) = Glancing Blow Reduction, BUT ONLY IF Glancing Blow Reduction > Physical Defense

and for Magical Damage:

RES (max value of torso's magical armor value) + CEL (max value of torso's evade value) = Glancing Blow Reduction, BUT ONLY IF Glancing Blow Reduction > Magical Defense

Here is an example of it in action:
Bob's torso has an Armor of 12.
He has a Scaled Defense of 22.
So, it only uses 12 Defense for the glancing blow reduction.
His torso's Evade of 35.
Bob's Scaled Celerity is 30.
So, it uses 30, since 30 is still equal to or lower than 35.
So, Bob's glancing blow reduction is 12 + 30 = 42.
42 is higher than Bob's Physical Defense, which is 22, so 42 is used for the Glancing Blow reduction. Remember, it is used instead of Physical Defense, because, well, it is higher.
However, if Bob's Scaled Defense was 50, then, since his Scaled Defense is higher than his possible Glancing Blow Reduction, it would always just use his Physical Defense instead of the Glancing Blow Reduction.

Basically, this method promotes dodge characters building small amounts of defense/resistance (up to the value of their armor/magical armor on their torso), as well as stops Dodgetanks from becoming too powerful (because oftentimes their Physical Defense would just be higher than their Glancing Blow Reduction).

Other things:
If the Glancing Blow reduction seems too low, then perhaps a base value of 10 could be counted towards the Armor and Evade of torsos, turning the equation into this:

DEF (max value of torso's armor value + 10) + CEL (max value of torso's evade value + 10) = Glancing Blow Reduction, BUT ONLY IF Glancing Blow Reduction > Physical Defense

In addition, if it did work for autohits, then we could have Evasion from Rogue add +4 per rank (max of 5 ranks) to the Glancing Blow Reduction (halved if not Mainclass Rogue).

And, one last thing: Glancing Blow reduction could cap off at 50, maybe. To prevent Evade 35 Ninja Armor Mainclass Rogues reducing each autohit by 65% damage.