Ehhh.... I want Vicky 3 to come when it's good and ready. Even after all this time, I think Vicky 2 holds up, and I'm worried about Vicky ending up like HOI if they rush it (substantial features of last game removed without a reasonable replacement leading to simulation issues for over a year after release).
I'm especially concerned about the economic simulation in Vicky 3. Paradox has had a simplification habit lately, and Vicky without a proper economic simulation isn't Vicky. 2's economic simulation wasn't perfect, but it was good enough that I voluntarily played pacifist (as in, 0 war declarations, 0 battles) games in Vicky 2. I have never done that in any other Paradox game, except for Stellaris, and had infinitely more fun in Vicky 2.
Yes, basically this. If they are going to do a lame oversimplistic economic system like EU4's or something, just to sell more, they might as well drop it and let us keep playing Vicky 2 which as you very well said, it holds up more than good. Because it has issues that we'd like adress, but mechanic-wise is still the best paradox game, as far as depth goes.