I think HOI3 was the shift. It really broke with the games that had gone before - and it ended up being a spectacular failure at launch. But it seems to me that lesson is what got us a good reboot of the Victoria franchise and then the stellar reboot of the CK franchise. All the stuff HOI3 got so wrong is what CKII gets so right; it's much more personal and immersive, where HOI3 went in the opposite direction even compared to the relatively clinical HOI2.
This is true for a different reason. HoI3 was our most abitious game ever, but sadly we simply tried to do too much. The effect was a release that was interesting to say the least. The lesson we have learnt it tone down our scope and put more emphisis on quality. You saw that in Victoria 2 and in CK2 we nailed it. We have a similar goal with EU4, if you want a radical rework of every single feature you are going to be disapointed in EU4.