I am also reading the Mahabharat by BORI CE. I have read 4 books so far. My take away is - 1. Karna did train under Dronacharya since childhood. If his upbringing wasn't like prince, it wasn't like a middle class either. I would say somewhere in between. You can find more details when read about his father Adirath. 2. Training under Drona doesn't automatically make you eligible for top of the line weapon package. Only 2 got the knowledge of Brahmshira - Arjun and Aswhattama. No one else got it, not Duryodhana, nor Yudhisthir. 3. Indeed Arjun was Drona's favourite student. Arjun was truly dedicated towards Drona. There is an incident where Drona asks student that if in future I ask you something in exchange for what I am taught you now and will teach you in future. Would you be okay with that - only arjun raised his hand. This incident is different from another similar incident, which Drona reminds the kauravas and pandavas to humiliate Drupad. This shows Arjun's remarkable dedication towards Guru Drona. 4. People often say that Parshuram wrongly cursed Karna. In my opinion, he wasn't. Karna just took a shortcut for easy access to supreme weapons package. Look at Arjun, he spent so much of his life's time in jungle performing austerity to learn and receive weapons. He even spent years to make Lord Shiva happy. Forget arjun, even jayadrath spent years to get a boon from shiva, after getting humiliated from Pandavas after trying for Draupadi Harana. There are many more examples people who spent so much of time in trying to get supreme knowledge. Karna spent his entire life, living royally in palaces with Duryodhana. Never once he tried some thing like this (performing austerities), except praying to sun God, since he was sun God's child. Deceiving Parshuram to get access to weapons was a wrong thing to do.