I hear that the provice layout for the N. American continent doesnt follow the state borders-which if true is going to make modding CSA, Quebec, possibly California more difficult. Meh. Any thoughts/issues/advice on potential issues for a HOI3 style Turtledove mod- do let me know. Forewarned is forearmed as they say.
I'm pretty sure that that is correct, provinces don't exactly follow the state lines.
However, provinces in HOI3 are alot smaller and more numerous there than they were in HOI2, so you'll have more room for fudging. You'll also have more of an ability to convey the epic scale of the conflict. Just for refrence, for example, the distance between a province roughly in northern Kentucky and the province of Sandusky (yes, its an actual province) is 5 provinces in a direct line. The rough area of the state of Ohio is something like 20 provinces.
So, yeah, its much bigger, which should help.
With the theater AI system and the ability to mod it, you should also have less of a "computer sends most of its army to Africa" problem that caused the creation of African puppet states.
Map wise, the HOI3 map is more easily modded than the HOI2 map, and in fact several mods have been released of it.
Problem wise, well, its bigger. You have more things to mod. Full judgment on this is going to have to wait till semper fi comes out, however, and we see how many of the issues in 1.4 it solves and what bugs/wonkyness it contains.
A few issues that are still around, so far as I know:
1) Threat can still quickly get out of control for axis nations if they don't know what their doing, resulting in a rush to the allies by all nations everywhere in the world. This can be manageable if the player knows enough to use spies to raise allied nations threat. The dday mod also deals with some of the core mechanical issues, so you might want to look at it.
2) Naval combat is in many ways still very wonky. Supposedly improved in SF, guess we'll see.
Overall, assuming SF is the improvement it looks to be, an HOI3 Turtledove mod should actually be genuinely superior in every way.