I did think twice about Parthy, but I wasn’t going to give him a chance to go rogue shortly after my funeral. He was too smart for his own good, so he died.
So you killed him just because you assumed he would turn later on? But what if he stayed good and eventually helped other dragons find the right path?
With absolutely no offence to any of you, this is like deciding 'hey, lets wipe out every single Arab, German, Japanese, Russian, Roman, Egyptian, Jew and North Korean, just to make sure they dont try anything funny again later on, as you never know...Ah, you know what? forget it! let's kill every human on the planet, they are too dangerous."
That just sounds so utterly wrong, after all...EVERYONE and every race, everywhere has done very bad things, but to want to not only kill them all, but to destroy their souls?....no....no no no!
Becides, I don't like the blades attitudes; If The Blades had a more compationate, even fear-of-the-unknown reason for killing Paarthunax, rather than say 'you're either with us or against us' and "we're not talking until he dies", then I would understand their reasons for demanding such an action; however, their arrogant, stuck-up, bossy attitude instantly turned me off (I also happen to love dragons), so I never sided with them.
It's funny really, the dragons of old wanted to kill all non-dragons in the world, yet the blades want to kill all dragons in the world....they have the exact same reasons (to survive!). The Thalmor also have the same attitudes to others, to dominate or kill all non-Altmer, and I dare say other races have had the same reasons too; The Dunmer used to keep Argonian and Khajiit slaves in the past. I for one HATE slavery! but would I murder every single Dunmer because of their culture? No way!
One good way of looking at this is to imagine that YOU are a dragon; how would you deal with this situation? To you, you'd see the Bipedals in the same way as they see cows or rabbits and so on (I.e you're 'better' than them)...you are not 'evil' for wanting to get rid of them if they dont do what you say, just like they aren't 'evil' for wanting to get rid of...say foxes, crocodiles, sharks or wild boars....it's all about the will to survive and not be dominated or 'enslaved' by others.
Anyhow, if you want to kill Paarthunax, then it's entirely up to you.... I however, let Paarthunax live; he's my Dova-bro!