Why don't people like to pick/use Tenacity over Determination?

[Kabooa]

While your theory is correct and relative to each previous step it is a steady increase of +25% eHP (and relative to the original it grows exponentially), the reason we call it "diminishing returns" has nothing to do with eHP; the core of the explanation was "you can't reach -100% damage taken stacking %-based cooldowns because of the calculation being multiplicative, not additive", i.e. 20% + 20% =/= 40% but 36%.

Apart from that, you mistyped the 3rd mitigation. That should be 48.8% mitigation (51.2% remaining) to give 195.31% effective HP; 51.2% mitigation would be 200%+ eHP.

Yeah, I mixed one up.

But that's also not what diminishing returns means. It means your effective gain is less. The effective gain is the same.

If it wasn't a geometric ratio, then you'd have increasing returns.

Right now it's neutral. Each gain is the proportional same as the prior - not diminishing.

For example

Stacking Direct Hit is diminishing return, even if no soft cap is applied.

1% DH is .25% average damage increase. At 10% DH you have a 2.5% increase of damage.

Our current baseline is [0], but we'll use [5] instead because it plays nice. 0 to anything is an infinite increase.

Every additional % of DH from the previous is 'less effective'.

5% -> 10%: "100% more chance"
10% -> 15%: "50% more chance"
15% -> 20%: "33% more chance"

Linear scaling improvement such as DH, Offensive Tenacity, and Determination have diminishing returns. That's before a softcap is applied.

[Argyle_Darkheart]

You get the same amount of benefit. There is no diminishing return.

20% Mitigation = 125% EHP.
36% Mitigation = 156.25% EHP (A 25% gain from the previous)
51.2% Mitigation = 195.3% EHP (a 25% gain from the previous)

The point is that stacking mitigation will mitigate less damage than if you were to use them separately, whereas the opposite is true for damage buffs. Effective HP is a separate matter; it is not equivalent to mitigation.

Linear scaling improvement such as DH, Offensive Tenacity, and Determination have diminishing returns.

This statement contradicts itself. Linear scaling is, by definition, not subject to diminishing returns.

The damage you would gain from increasing your direct hit rate from 5% to 10% is the same as the damage you would gain from increasing your direct hit rate from 10% to 15%. The relative increase in direct hit rate is entirely irrelevant with regards to actual output (damage).

[Kabooa]

Stuff.

I feel like we're tackling the same thing from different sides.

I say DR doesn't apply to mitigation because EHP increases at a proportional amount, while you say it is because the raw damage itself is decreased for each additional instance.

I say DR applies to things like DHit because the relative increase is smaller for the same budget, while you're saying it's not because the raw increase is the same.