PRR is a stat that suffers significantly from diminishing returns. The first 50 points of PRR add a lot to a character's survivability. The next 80 add a fair amount too, but then additional points become almost entirely meaningless.
The difference between 200 PRR and the ridiculous, unattainable figure of 1200 PRR is the difference between taking about 42% of raw physical damage and taking 35%. (For comparison, the difference between 150 AC and the ridiculous 750 AC is that the 750 AC character would take only 20% of the melee/ranged damage the 150 AC one would).
Above 160 or so, PRR is a totally worthless stat.
This means that unlike other defensive stats (dodge%, AC, HP), the more of it you already have, the less each new point helps you. And the diminishing aspect is very marked. We have a strange setup where the defensive EPLs (Bladeforged, Divine 1, Divine 2, Divine 3) provide almost nothing to characters that are defensively specced, whilst being very powerful (when stacked) on casters or other 'glass cannon' types.
I don't think this can be fixed without rethinking PRR's formula.
1) Adjust the PRR formula so that damage taken is calculated as follows:
Damage Taken = 100/(100+PRR) * Raw Physical Damage
So a character with 10 PRR would need to suffer 110 raw physical damage to lose 100 HP. A character with 150 PRR would need to suffer 250 raw damage to lose 100 HP. And so on.
2) Because this improves the value of PRR, readjust downward some PRR sources in game, with a general goal of dropping player PRR by 20%. This should keep characters at about the power they are now, but while making PRR easier to understand and letting it scale better.
Quick note: The exact mechanics of PRR are as follows:
- 35% of damage ignores all PRR, no matter how much you have
- The other 65% of physical damage you take is decreased by 1% for each point of PRR you have, stacking multiplicatively.
So the Live formula is
Damage Taken = (0.35 + 0.65 * 0.99^PRR) * Raw Physical Damage