The "plot" for Dominique seemed to be, "Look at us! We have a Black person on our show!" Plot over.
If Dominique is going to be the only Black person on the show then they should not make her a morally reprehensible person. However, that doesn't mean she has to be
a well dressed cypher. She could have been a strong, intelligent woman with basically a heart of gold, but not adverse to using her claws when the situation called for it.
@Michael Torrance has some good ideas for putting her at odds with Alexis. Everything the show did in that respect was so forced. The way they had her come in so fascinated by the Carringtons, including Alexis made it a story about a Black woman desperate to be white, imho.
I would have liked if instead of her coming to the Carringtons they came to her. Tom admits to Blake on his deathbed that he has a daughter. Blake seeks her out, but she is somewhat disdainful of him because of his noteriety. She looks down on Alexis even more because of Alexis's reputation via the scandal sheets. She treats Alexis the way Nicole treated Angela over on Falcon Crest. This of course infuriates the first Mrs. Carrington to no end.
It would be great if Blake's prejudice surfaced its head at first, and Krystle has to guide him with her cool wisdom. Dominique and she becomes friends and Krystle, at some point, Krystle tells her about Alexis causing her miscarriage. Dominique is horrified and enraged, and decides that if Blake won't give Alexis her comeuppance, SHE will.
While I'm rewriting Dynasty, more Billy Dee Williams. Maybe he and Claudia could have a flirtatious rapport/affair. Dominique is not amused and her not so nice side comes out.
I also thought the actor John Amos could play a tough businessman who enters the fray at some point and is a formidable opponent for Blake. I always thought John Amos was a good actor and can play "tough, hard-nosed" very well.