Stupid thing about sliders is that it only made sense to go in a single direction for most of the sliders.
Like Centralization was a guaranteed take over decentralization.
That is true, in the vanilla game a lot of the sliders were obviously one sided but that could have easily been fixed by simply balancing the modifiers, the Death and Taxes mod did an amazing job at balancing the domestic polices. It is also worth noting that centralisation would almost always give you a negative events, so it was not completely one sided. It also took a long time to move even one slider to your preferred position, which was good, it made it feel like there was real long term change.
The biggest problem I had when transitioning from 3 to 4 was that the improved 3D graphics made the world feel very fake. 3 felt very atmospheric and that was awesome. 4 just feels too much like a game I guess.
I would agree with that somewhat, the map on EU3 had a certain level of beauty to it that doesn't exist in EU4 because, well its not a map any longer. I imagine they made that change because it draws more people into the game, I mean from the outside a game like EU3 did not look appealing really until you got into it, but with the maps like they are in CK2 and EU4 I think it would be a bit more appealing for people who have never played a game like EU4 before.
That would make sense considering EU4 and CK2 are Paradox's two most popular grand strategy games by a fairly long way if I remember correctly.