Hate to jump on a bandwagon, but yeah, HOI3 was horrible! The only PI game I've played and genuinely not enjoyed. It's thoroughly confusing, even by PI standards, not remotely newbie-friendly, graphics suck, sprite packs don't work, ugh! I've tried 4 or 5 times to get into it, and just couldn't. EU3, EU4, CK, CK2 and Vicky 2 I've loved, Sengoku and EU Rome not so much, but I've had some fun with them. HOI3 just no. I hold out hope, WW2 is something that could and should work so brilliantly with that Paradox approach, so HOI4 can be great, but the graphics, user interface, accessibility, freedom of decisions and some other bits all need to be markedly different from what's gone before.
If PDS make the right decisions, this could be a fantastic game. Make the wrong ones and well, a polished turd is still a turd.