I think you both have a point, but as a reader of those things that don't exist, they really butchered the Dorne storyline. It barely resembles the storyline from those things that don't exist. Other than maybe a casual mention, I think they are probably done with Dorne. From a tactical standpoint, Dany no longer has any ships to transport the Dornish army and they are stuck at the extreme south end of the continent with the now "Tarly" army directly to the north.
Although I liked how someone earlier contrasted Tywin with Cersei. If it was Tywin, he wouldn't have killed Ellaria and her daughter, he would hold them as hostages or marry them off and force Dorne to fall in line. Cersei is so scorched earth and damn the consequences that they could bring back the Dornish army fighting for Dany in some way later on. If anything, Jamie is acting much more like Tywin now, getting a lesser lord like Tarly to turn on Olenna was straight up Tywin's moves against Robb with the Frey's and the Bolton's.