I like the new tech system, it feels more balanced and rewards you for be ahead in research during ck II timeframe.Its working as designed, and during the time of 769 and 867 it isn't far fetched to put the Indian's as the strongest technologically. That is how the history files for CK2 are scripted. How it is right now is that it calculated a median value of everyone in the world, those that hits over that mark with a good margin becomes western, if you are near the median then you are eastern and if you are way below then you get something much worse.
Perhaps the thing that should be dependent from culture/religion are units types.
I mean seeing in eu IV a western tech indian nation with galloglaigh units and a muslim thec TO with muslim musketeers feels weird.
Also now unit types are balanced in eu IV so it should be fine.