Now that you guys have joined the dark side...
But seriously. There are obvious engine parallels to (older) Paradox games. I actually brought this up on Paradox forums and probably, and both sides claim that it's a "coincidence" that the engines look and work so similarly...
Now, why not have a Great Invasions II on the Clausewitz (EUIII/HoIIII/Rome/VickyII) engine? It's one of the few periods Paradox grand strategies didn't cover, and it would benefit from having more than 1 man on the team.