You have people of Chicago, short people, and people of third world countries people whose association with the following prepositional phrase is an accident of birth. Obviously, the connotations of heiress are unfortunate, conjuring up Regency damsels wooed for their fortune. But inheritors is a vaguer word than heirs. It may come in time to have the same connotations as heir, but it doesn't now. Seed is a graphic, earthy metaphor, extremely charged and potent, stretching its potential into the distance of time in a way that children just can't.
Seed has possibilities of descent that are limited by the term children.
Not Lord and King Hierarchy itself as expressed in liturgical language is seen as oppressive. We are urged to be sensitive to and avoid such words as Lord, king, kingdom, and anything else that not only might have masculine connotations but hierarchical connotations as well. The proposed substitutes, when substitutes are proposed, are words lacking the connotations we have come to associate with a phrase like the Kingdom of Heaven . Savior implies gratitude, but Lord implies obedience. I don't think we'd better get rid of Lord .