I at one time had the most evil character that I have had in any game. I still couldn't bring myself to kill Paarthurnax. He lives his entire life suffering for what he did in the past, and never looks back. I would like to see the Blades wishing him dead after talking to him and learning from him like the Dragonborn does.
I know there's another thread on this, but there's a line Paarthurnax speaks at one point that I really like:
"Zin krif horvut se suleyk."
It means "honor is fighting the lure of power." This dragon is an inspiring role model. That's why he's awesome and doesn't deserve to die.
I agree
If anyone deserves to die it is the Blades It is long past the time when time their ignorance, arrogance, and wrong headedness be brought to an end. They failed to protect the last Dragonborn, and also dismally failed to defeat the Aldmeri. Their history involves repeated incompetence and tunnel vision. They even failed to uphold the traditions of their own beliefs. Why should the Dragonborn either listen to or trust them?