To be fair, a lot of the independence stuff was tempered by British promises of fight for us = more independenence. Something their diplomats were promising freedom very freely, especially during the period where it really looked like England might get invaded. See promising both jews and arabs the holy land for the most well documented of these instances
But all this political stuff deserves much deeper models to fully represent. HoI is not however the game to do so, it's primarily a combat game compared to the other pdox titles. So the question is really; how best to represent and create a situation where;
1) India is well defended
2) A player is motivated to defend it, and abandonment is nonsensical.
3) India provides military might to the Brits in Europe and elsewhere
4) But still not too much! No Indian horde manning the Maginot Line.
?
Personally I am willing to accept some solutions that sacrifice a bit of historicalness to guide players into making similar decisions to real life, since a lot of political stuff cannot be modelled.