But *India* is a modern concept - it really came out of the British Raj more than anyting else. There were states that ruled large parts of the subcontinent in the past, but it's not like China where there is a reasonably consistent line of different dynasties ruling the same state, it was completely different, often unconnected, empires ruling over some of the same territory.
The people in the Mahabharata weren't Indian - again, this unified nationaility is a new thing - any more than Mughals were, or Mauryan's were, or the people of medieval Vijayanagara were, These were their own states, with their own histories and culture and deserve their own identity in the game, not being amalgamated into a modern identity based purely on the fact that they owned parts of the same territory, particularly given some of the "civilisations" that have made it into the game (*two* Amerind tribes, Polynesia, the Huns....).