Found some issues with the tech growth. I get its supposed to be slow, but the increasing base cost and huge ahead penalties should cover that.
This may be intentional, but tech growth only uses the rulers attributes, NOT the state attributes? As a consequence, military seems to grow way faster than the others because martial is way easier to boost then learning or stewardship between artifacts and minor titles.
Also, the buildings are way too weak. Each one is equal to a single point in the relevant stat, and all but the blacksmith and the tower university require tech for even level 1. So as long as you play fuedal, you have to spend money on buildings in vassal baronies to get any non-military tech from buildings if you can't acquire a tower. And tech growth doesn't even scale with building level, unlike everything else.
Btw, why are temples so much stronger for tech buildings? None of the religions seem to have a heavy enough emphasis on knowledge to justify being the only common holding that produces research outside its specialty and producing twice as much per tier.
And the note of holdings, many of the unique buildings are pretty horribly underpowered. The temple of the one costs 360 gold and about 2 decades or so to build for +1 gold income, and the arcane university gives 50 mages in exchange for 1350 gold and 2 decades of build time. In the universities case, that's 2 or three new HOLDINGS worth of resources. And those are both weak bonuses. 50 mages isn't much when they don't get any of the troop quality upgrades from temples, after all. If something is in the price range of a holding, it ought to be GOOD.