[Sawrock]

Ogata's Waraji (+2 CEL, +10% Physical Damage Reduction) only works when wearing unarmored armor.
Black Knight's Indomitable (+10% Physical Damage Reduction, doubles if Black Wind is used and if Black Knight is your main class) only works when wearing heavy armor.
In my opinion, this makes Ogata clearly more useful- you can be dodgy, and get tankiness as well. While Intomitable is situationally more useful, it's just that- situational, and otherwise the same bonus. It also, mind, doesn't provide the +2 CEL boost that Ogata does, and while that may seem a small stat boost, it it still an advantage none-the-less.
These are some suggestions that could be used to fix the situation, in my opinion:

1. Changing how Indomitable works
Make Indomitable start with 10% damage reduction, add 10% if you used the Black Wind (without requiring Black Knight to be your main class), and then, if Black Knight is your main class, add 10% more damage reduction as well. This leads to the following scenarios:
10%: Heavy Armor, BK Subclass, No Black Wind
20%: Heavy Armor, BK Subclass, Black Wind
20%: Heavy Armor, BK Mainclass, No Black Wind
30%: Heavy Armor, BK Mainclass, Black Wind

2. Changing how Ogata works
Make the physical damage reduction on Ogata work like Evasion from Rogue: it works only on autohits if you would pass an evade check to reduce the damage.