For political expediency he encouraged it (In divide and rule - nehru exceeded the brits by a wide margin). The Madras Presidency was headed by C Rajagoplachari, Free India's first Governor General. Splitting Madras Presidency was nehruvian strategem to cut C R down to size since he was a eminent leader post Patel's demise. He played the same game in Bombay presidency where the real targets were Morarji Bhai and Yashwantrao Chavan.
On nehru's econonomic blunders, the effects of which were obvious even in 1950s read out old editions of Swarajya and what JRD advised to Nerhu. The lamentation of erudite people could not move nehru to pragmatic approach and he continued with his quixotic ways. His mixed economy model was nothing but command and control communist approach resulting in cronyism and perpetuation of poverty for two full generations.
With India's industrial infratructure in 1940s it is a shame that china over took us in nuclear and space technologies.
neru's sins go far and deep. pls do read out insider (PVN) on what he has written on neru's socialist pattern (Since PVN was a dynastywallah and active politician, you have to read between the lines to make sense of how according to PVN neruivan congress socialism conned India).
Even better sources will be Frank Moraes and Bhagwan Das, editors of Indian Express and Hindustan Times during the neruvian times. Bhagwan das's biography is outstanding in this respect.