Game Of Thrones: 10 Worst Changes From The Books
6. Tanking The Dornish Plot
The massive scope of George R.R. Martin's A Song of Ice and Fire means it would be next to impossible to include every detail, character and subplot. Even with axing a huge amount of material, the show runners struggled to resolve their remaining plots succinctly and in a satisfying manor.
But they still made the mistake of entering into plot lines they had no intention of finishing. The introduction of Oberyn Martell, and his death at the hands of the Mountain, kicks off a whole series of events in the books.
The Dornish scheming is some of the most complex in the story: They send a Prince on a secret mission to marry Dany and claim her dragons; they attempt to put Myrcella on the Iron Throne after Joffrey dies. They're also in talks to team up with the long lost son of Rhaegar Targaryen, who is in fact half Dornish. This house basically has a contingency plan for any outcome, and will more than likely play a huge part in tipping the scales one way or the other.
Sadly non of this was explored in the show. Introducing a brilliant character like Oberyn soon became redundant when the remaining Dornish characters drifted into obscurity.