I don't think a modern game is likely Supreme ruler 2020 was recently released and they would be in almost direct competition.
My opinion is HoI 3 for next project. Why?
1. HoI series is a big money maker for Paradox (so I've heard) and is still very popular.
2. Most of the game mechanics have been developed refined from the many patches/expansions to date. A graphics update to EU 3 engine, with a few new features, would allow a greatly decreased development time
3. I remember seeing a 3d tank in the Paradox April fools screenshot.
