As a Returned, Blushweaver is very different from regular beings. Physically, Returned are stronger, faster, and embody physical perfection. Because of her divine status, Blushweaver is much more than a regular human. She is godlike, and that’s how people treat her. Consequently, her perspective is also very different from normal beings. To her, humans are average, and rarely deserve special attention. Perhaps Elhokar can be forceful and adept sometimes. Perhaps he is very similar to Lightsong in certain ways. But there’s one thing he lacks: He’s not a Returned. To Blushweaver, Elhokar doesn’t deserve any kind of attention or help, even if he is a king. In Warbreaker, she treats Siri with little respect, even before Siri and Lightsong become friends. This shows that she has little to no regard for royalty. For all she cares, Elhokar is a toy and a tool to get what she wants.
Even if they did fall in love, their ways are too different to make either happy. Suppose they did like each other. Suppose, something outrageous happens and they completely fall in love. There are two options now: Elhokar can come to live in the Court of Gods, or Blushweaver can come live in Alethkar. Elhokar can show strength sometimes, but deep down he has an intense paranoi that would only increase in a place like the Court of Gods. Being somewhere where he is regarded as puny, among gods who could squish him if they wanted, would dramatically increase his fear. He would never be able to shake this intense anxiety, and as a result he would never be able to really be happy. In Blushweaver’s case, living anywhere else would be dull, boring, and not worth her time. In the Court of Gods, she can eat anything she wants, do anything she wants, and all whenever she wants it. Even if Elhokar had enough time and resources to find a way for her to stay alive on Roshar, the Alethi Court would be nothing like how she is used to living. Elhokar would likely give her whatever she wants, but the speed, the ease in which she gets it could never match the Court of Gods. And, the way she is treated would drastically change. She would be revered as a queen, but not a god. The Alethi have their own religion, completely separate from what Blushweaver is used to. Maybe she would be astounding. Maybe she would seem divine. But to them, she’s still no god. Even if she loved Elhokar, she would never tolerate living in this way.
So, even if Blushweaver somehow went against her nature, her upbringing, and everything she has learned and fell for Elhokar, being with him still wouldn’t make her happy. Elhokar could very likely fall in love with her, but at what cost? Neither are alike enough to have a normal, healthy relationship, and trying to live in the other’s situation would only make their own worse. In conclusion, Blushweaver and Elhokar could never be able to have lasting happiness together.