Hard to say, really. HoI3 has a lot more to it, and splits units even further, so that when you build your divisions you decide what types of brigades make them up. Also in HoI3, the war system is changed a bit, so that you have to have your neutrality at a certain point depending upon the other nation’s threat level before being able to declare war on them, whereas in HoI2, you could just go for it, but risk that a major power stops your expansionism if you hit someone whose independence they have guaranteed. If you plan on ever playing a minor power, then don’t bother trying to do it in HoI3, it’ll take you 12 months solid to be able to hit anyone else, regardless of which nation you pick. If you plan on only doing the bigger countries that were involved in WW3, then it won’t make a difference.
HoI3 also has more glitches to it, but you can expect them to be fixed by patching.
Really, it depends on if HoI3 is too much micromanagement for you to handle, or if you want to ever play a minor power such as bulgaria or brazil.
