It's quite the stretch, going from modding a very mod-friendly game to making a whole new game, you know. In fact, there's a reason we havent seen mods-turned-games from the HoI4 modding community, modding skill does not translate into game-making skill. Hell, you talk of coding, but you are aware that technically speaking the vast majority of the "coding" in HoI4 mods is actually scripting?
In other words, you seem to have too high an opinion of the skills required for HoI4 modding. In fact, I'd say this game is the RPGMaker of strategy games in that sense, we've seen all sorts of whacky things done with RPGMaker, because it's easy to master and twist to unintended ends, just as HoI4 is, to varying degrees of success.