After playing tonight I can say that the general increase of costs for economic is good, but it might be a bit too extreme for now. I don't know whether it's wise to ask of the player to invest ~50000d (~60000d with 20% infl.) as the OE at Orthodox tech (without Persia), for infra 6 in 1633. For now economic techs basically turn off, and while this is the idea it certainly makes the option to go competing against Austria in land tech a no-brainer. The end result is Austria will have a harder time achieving land tech superiority on me because I have little reason to invest while economic tech cost remains that high.
I guess the true test for this system first comes though when a game is played from scratch on it. Unfortunately, it will take a few weeks before it gets somewhere and you actually can assess the effects. For example the OE I play would not have gotten trade 6 in the first place from whereupon to research trade 7 had this game been played with higher tech costs from start.