Should it have happened? Should it have happened as it did?
What level of input should leaders of the Princely States have had? The Indians invaded Sikkhim, which was never part of British India, because of the populace, yet they used the claim of the Hindu prince in Kasmir to annex them, despite them wanting to be an independent state. This also went for Bhopal, Travancor, Hyberbad, and a number of other states. Having Bengal be unified or seperate from Pakistan was also never an option, neither were the Dravidians(Those who made sure English was one of India's official languages instead of just Hindu) given the chance of their own, as most of their independent states where then invaded.
As for the states made on religion.... Hindu seems to just a title used to plaster over the non-Abrahamic beliefs of the Ganges watershed. This ignored the local diversity, overwhelming local majorities, causing it to basically be that only some regions with absolute Muslim majority where placed into Pakistan, a land which had the Punjabi dominate Bengal, despite Bengal having a majority between Pakistan. A Sikh Khalistan is Punjab was also ignored, despite how the region was divided between Hindu and Muslim and having a highly militant group who's beliefs were a fusion of both might have helped.
