The lack of apocalyptic wars is because, firstly, human players tend to be much more reasonable than either the AI, or historical politicians; and secondly, the warfare model is a bit broken. Armies can disappear completely, which basically never happened in real life; there's no model of last-ditch Volksturm mobilisation - the partisans are annoying, sure, but they're not a serious threat to someone who has no regular opposition - and, of course, only bits and bytes are dying, so you can't pressure your victorious opponent by saying "Well, you've got me, but I can still kill another half-a-million of your countrymen". (Real politicians tend to be sensitive to that sort of thing, oddly enough.) So wars usually end as soon as one side or the other gets a clear advantage. The sort of equally-matched stalemate we've got on the Persian front is pretty unusual, and even that relies on our stacking rules - if China could just put its entire army in one big Dragon Attack Stack Stance, their superior numbers would roll right over us.
The Twenty Years' War in the other timeline could happen because I was fighting the AI, which is designed to put up a good fight rather than be reasonable and save its country for another day. If Burgundy had been human-played I'd have been crushed like a bug. (Then again, possibly I might have built a larger regular army in that case.) So playing humans has its pros and cons - you get a lot of interesting diplomacy, but the purpose of diplomacy is after all either to avoid actual fighting, or else to make any fighting that does occur as one-sided as possible. So you get rather fewer apocalyptic, fight-to-the-last-ditch, mobilise-the-girls-of-twelve wars.
The Twenty Years' War in the other timeline could happen because I was fighting the AI, which is designed to put up a good fight rather than be reasonable and save its country for another day. If Burgundy had been human-played I'd have been crushed like a bug. (Then again, possibly I might have built a larger regular army in that case.) So playing humans has its pros and cons - you get a lot of interesting diplomacy, but the purpose of diplomacy is after all either to avoid actual fighting, or else to make any fighting that does occur as one-sided as possible. So you get rather fewer apocalyptic, fight-to-the-last-ditch, mobilise-the-girls-of-twelve wars.