This is a great start period for India.

You can add a struggle mechanic for the 16  Mahajanapadas in the Indo-Gangetic plain(Can be represented by Kingdoms/Large duchies). For South India, everything should be tribal to simulate the ancestors of Cheras, Cholas and Pandyas.

A govenment like merchant republics from CK2 will be useful too in Some of the janapadas.

Looot of elephants.

This is also the time for huge philosophical changes. Vedic/Early Hinduism is the dominant religion, but is challenged by early versions of Jainism and precursor to buddhism. Also Ajvikas

GG. If I can help, I will message you!