I don't disagree on any particular point, though I think she's more stupid than evil. She just can't think of a more clever way to deal with things.
Like The Vampire Diaries... I can't think of a single character who was killed that didn't come back. Some several times. I just roll my eyes when they die.
I did not roll my eyes when Oberyn died.
Yeah, I think BJ was the only person on Earth bummed when Joffrey died. He was like "Nooo, he was supposed to take down the Lannisters from the inside! Now the grandpa's going to fix everything! Lannisssttteeeerrrrssss!"
Overyn's death was less brutal in the books though. I feel like this and Talisa's death at the red wedding were specifically written to keep book readers on their toes. In the book, if I remember correctly, Oberyn just takes one massive punch that caves in his head and it's over. The toothless screaming with thumbs deep in his eye sockets... I totally covered my eyes but peeked through my fingers.