This Tech-tree is probably the most representative of changes I though the game needed, overall developments still goes on and it's done when it's done, of course.
The Industrial tech tree : Some aspects are inspired by Mod34 and CORE. It now represents countries development status and it's limitations, this means no longer Tibet will be able to research production planning techniques if they're not industrialized. The tech-tree also covers social aspects such as propaganda, population census, medicine etc... Which where quite important during war times.
It is also useful to reduce the number of "developement" events that most mods have, as the player/AI can do quite detailed reforms/industrialization through the tech-tree and the game engine. Some buildings costs, production and effects have been divided by two to make them easier to manage and to have quicker effects. For example now if you build IC it will costs you 2.5 IC, you'll get 0.5 IC, it'll build faster and more important it'll be fairly more manageable for a countries that have 5 IC.
Back to the tech-tree. Perhaps some may argue that the number of techs is probably too much to research for one country but it's actually designed for, it's up to the player to put some priorities and to not waste time and tech-slots on unnecessary applications.
I also took some time to rewamp Ideology matrix : It now much more easier to be authoritarian, but if you want to go totalitarian, be it right winged or left winged, it will requires extreme sliders positions but will be also more rewarding/secure if you come across some random events.