I spent some time plotting out the armor damage reduction and your calc is off by a bit.

Here is the formula derived through testing:
0.206+0.0173*x+-0.00000243*x^2+0.000000000212*x^3+-7.93E-15*x^4

See here: https://docs.google.com/spreadsheets/d/120ozrDRY03-X2BE82OoMICoidKr--JJdRGBDtIywUz8/edit?usp=sharing

This is super minor and i suspect few people care, its most important that the table is correct for lvl 60-63 targets after all.

The formula seems to be incorrect for targets of very low level relative to player. The table reports that i should have 73% crit vs lvl 25 targets, but it definitely does not feel accurate ingame. Feels more like ~25%.

Hey, just wanted to say your tools are very useful. But I did want to point out the the DR/effective health calculator is using the formula from TBC. The Vanilla Formula is DR = (Armor / (Armor + 400 + 85 * Enemy_Level)). For example, the cap for a level 60 player against a level 63 boss should be 17,265 armor.

it seems the way dual wield miss chance is calculated here only applies the dual wield penalty to the baseline miss chance of 5%:

Baseline = 0.05
if (defense_rating - attack_rating >= 11)
Miss = (defense_rating - attack_rating)*0.002
else if (defense_rating - attack_rating <= 10)
Miss = (defense_rating - attack_rating)*0.001

function Dual_wield_penalty(x)
return 0.8*x+0.2

Dual_wield_miss = Dual_wield_penalty(Baseline) + Miss

Should the dual wield formula apply to just the baseline 5% miss chance as in this simulation? The attack table source seems to imply it applies to the overall miss chance "Beaza also tells us that the dual-wield miss chance is 80% of the miss chance calculated above plus 20%, which makes the dual-wield miss formula", making this instead:

Dual_wield_miss = Dual_wield_penalty(Baseline+Miss)

https://github.com/magey/classic-warrior/wiki/Attack-table#glancing-blows
(original source https://wowwiki.fandom.com/wiki/Miss?oldid=347982)

It looks like the aoe 1/3 coefficient is left out and Bonus heal is overstated.
The coefficient should be 3/3.5/3 = 0.286 (instead of 3/3.5 = 0.857)