Would be hard to "port"(sell as a DLC) WoTR archetypes and races into Kingmaker?

IDK how “reusable” the WoTR content is. But I will be honest. I have over 800 hours on kingmaker and honestly, being able to play as Cruoromancer and other WoTR classes would increase a lot the “replay value” of Kingmaker IMO.

Alternatively you could use the CoTW mod and a few others, which should give you way more races, classes, archetypes and a ton more class options than a Wrath port could give you.