Karna in the Mahabharata is like "a water droplet on a lotus leaf " or like mercury in the plam to give a more modern analogy, cohesive, contained in his Self ... In the world yet not of the world ..
Inspite of the really negative company of Duryodhana, Dushasana and Skahuni he is relatively righteous. Everyone makes one or two mistakes, Bhishma made some, Drona made some and so did he. Big deal !
On one hand we have Arjuna who falters at every step and has to be practically handheld by the Lord and on the other hand we have Karna who gives his everything away in charity, to mortals and immortals .. forgives his mother who cast him away as a baby .. protects his brothers by never letting them know that he is one of their own .. and dies the most glorious death on the battlefield, forsaken by mother Earth, forsaken by his Guru, forsaken by his very father the Sun God ... brave and alone ... fighting his destiny to the very end ...
No mortal man or immortal God can ever bear up such a burden so well as him, neither Arjuna nor Bhishma neither Devendra nor Surya. Even Krishna himself cannot inspire such awe and respect for he has no destiny to fight against, neither adversity, nor sorrow, nor a glorious divine heritage of the Kuru dynasty that was denied to him. He is perhaps the most admirable character in the entire Mahabharata, and certainly one worth emulating.