My only game of any length there, and also my most memorable one there was on the 769 start as that one OPM between the Abbassids, the small sunni kingdom to the east, and I think the zoroastrian duchy to the north maybe? Did about 30-40 years or so I think and got the entire sunni kingdom to the east, (I gained the first county just as I lost my original one, drastic reduction in power since the only border county into the east is garbage in upgrades compared to the original one) and then I ended it. I was trying out deadly plague at the same time and it kind of ruined things for me there. Since it seemed to get stuck (about 60 years of just sitting around fast pacing it and it was still there.) and made it so there was no supply anywhere, and no levies either.
If not for that I would have probably played on and conquered India or something. Maybe taken just that one original province from the Abbassids just because. (Abbassids took it in the end, but originally I lost it to a peasant revolt...)
Though to be fair RoI is pretty shit, there isn't really much of a point to India unless the player directly interacts with it. Even if you are playing right next to India it doesn't matter unless you intend to interact with India. They never do anything beyond India, and the AI from outside never does anything in there either. I always just see it form into the three kingdoms and then just stay there for the entire game, with the only reminder for its existance being the event for traders or whatever that give you an eunuch.