4 attempts and I finally have achieved 'The Buddhists strike back'
Taking all of India and converting it to Theravada Buddhism isn't easy, but once you are past the initial powerhouses of Vagina-Guard and Bad-Man-Is it isn't really hard going. I must admit that since the latests patch playing Buddhist expansion is at least viable and not instant suicide, but I still found myself running negative Karma for a good part of the game (although thankfully I had enough momentum to overcome the military weakness). I would like to see them add some more interesting balance points to having negative and positive karma, just so it isn't and instant nerf if you stray to far from the middle ground.
Converting Nepal to Theravada and spitting them out as a vassal helped me to get this done before 1700, could have managed it quicker if I had been min-maxing my province ceding and claims but once you get over a certain size it really just becomes a case of when and not if you finish.
