As I read the Forum, I pick up points and questions and address them as I see them.
We should, and since the construct never takes off his helmet, I won't have to grind my teeth at a 25 year old playing the part of a 36-44 year old.
Remember that Oberyn used a very slow, very painful poison and that the Mountain's screams were heard throughout the castle until Cersei has him sent to the dungeons? the Red Keep? to die. I don't remember where he ended up. And he ended up lasting well into the next book iirc, albeit in pain and never really seen again.
Concerning Oberyn Flynning and doing acrobatics etc. in the duel: I originally hated it and thought it was silly and then I as I watched it a second time, it occurred to me, of course Oberyn would do the acrobatics and showy flashy fighting. Who else would do it but him? That is exactly the sort of duelist he would be. And then I started to appreciate all the unnecessary flourishes and spins and things that just wouldn't work in a normal gritty Westeros duel.