Well think of historical/ahistorical I think there are four ways
1. Historical actions with historical outcomes i.e. Germany invading USSR, made some initial gains, but finally lost the war. And I think HOI2 has been quite well with this, at least, if you human don't do anything which changes the balance of powers dramatically, things tend to follow the historical path, but historical outcomes that depend on game progresses i.e.war with Russia, will be difficult to simulate a historical outcome.
2. Historical actions with ahistorical outcomes - this I think, also involve in-game progresses and whether turning on/off doesn't matter but require more of a sensible AI decision. For example, Operation Barbarossa under AI almost always happens at July 1941, but the outcome might be that Soviet getting crushed. This I think, is difficult to say historical or not, especially if some linked events don't have a historical outcome the rest of them then will not be able to go historical i.e. France didn't fall to the Blitzkrieg, Holland and Belgium never capitulated, and in the end everything ended up as a trench warfare; should German AI still invade USSR at 1941 then?
3. Ahistorical actions with historical outcomes - This is what happens when we simply don't want to follow history and start to do random things. And basically I think when things are going so ahistorical it's really difficult to force the AI to go back down the right path. Even something really remote may greatly altered the final outcome. I think the present events structure of a AI chance 100/0 and how the events are scripted may ensure that most ahistorical actions will not have dramatic effect on the outcome of other things.
4. Ahistorical actions with ahistorical outcomes - if the game follows this then the AI should matter the most i.e. by making the best decision and reaction, for its best interest. Also we will not expect any events to happen that will follow the historical part. The AI is most important but there should be no problem with this.
Conclusion: I think the present system is OK, whether an option to switch historical accuracy doesn't seem too big a deal - if you want historical accuracy, you should avoid doing things that will dramatically change the conditions.
1. Historical actions with historical outcomes i.e. Germany invading USSR, made some initial gains, but finally lost the war. And I think HOI2 has been quite well with this, at least, if you human don't do anything which changes the balance of powers dramatically, things tend to follow the historical path, but historical outcomes that depend on game progresses i.e.war with Russia, will be difficult to simulate a historical outcome.
2. Historical actions with ahistorical outcomes - this I think, also involve in-game progresses and whether turning on/off doesn't matter but require more of a sensible AI decision. For example, Operation Barbarossa under AI almost always happens at July 1941, but the outcome might be that Soviet getting crushed. This I think, is difficult to say historical or not, especially if some linked events don't have a historical outcome the rest of them then will not be able to go historical i.e. France didn't fall to the Blitzkrieg, Holland and Belgium never capitulated, and in the end everything ended up as a trench warfare; should German AI still invade USSR at 1941 then?
3. Ahistorical actions with historical outcomes - This is what happens when we simply don't want to follow history and start to do random things. And basically I think when things are going so ahistorical it's really difficult to force the AI to go back down the right path. Even something really remote may greatly altered the final outcome. I think the present events structure of a AI chance 100/0 and how the events are scripted may ensure that most ahistorical actions will not have dramatic effect on the outcome of other things.
4. Ahistorical actions with ahistorical outcomes - if the game follows this then the AI should matter the most i.e. by making the best decision and reaction, for its best interest. Also we will not expect any events to happen that will follow the historical part. The AI is most important but there should be no problem with this.
Conclusion: I think the present system is OK, whether an option to switch historical accuracy doesn't seem too big a deal - if you want historical accuracy, you should avoid doing things that will dramatically change the conditions.
