[Autumn]

Ghost gets a +6 RES passive and +48 HP passive. Kensei gets a +3 STR SKI passive while both of these classes can apply for Vent Petale too (yes even Kensei). There is no reason Firebird shouldn't have a passive too.

Problem with this line of thinking is, I don't think those classes should have all that they have to begin with. They both get a load of stats, but that doesn't mean that's a good thing that more classes should be doing. I don't see how having points in DEF mitigates free DR from having WIL in Boxer's case, afaik it just adds to DEF's DR number. It's not a separate instance of DR that's multiplicative, it's just added to the number that's already there.

Since you don't seem to be aware, Weir Kounen and Stand Off scale in a way that is identical to multiplicative DR instead of additive, if you have 50% Phys. DEF for example, 60 WIL would not add 12% DR, it'd add 6%. Where as if you had 0% Phys.DEF then you'd gain 12% Phys.DEF.

This means it is slightly better than effects like Weathered Body or Indomitable, but the DR you get from it is so little that many other passives outscale it entirely and make these skills very weak in comparison since the others don't have very steep stat requirements.