Also revolt risk should spike up dramatically once war is declared and troops start leaving the nation, just to simulate that rebellious elements might seize their moment to attack. This would mean that the AI and player would be required to maintain some home forces or risk rebellions at home. Hopefully this would stop nations from emptying out all troops from their lands during wars.
This is part of something I really want to see. A good part of the reason why nations such as Ottomans, PLC and Russia didn't immediately gobble up everything near them or actually had to sign disfavourable peace deals despite not being beaten in a ''total war''-scenario is because:
1) Internal factions didn't want the king to have power. Standing armies and such were dangerous as it allowed rulers to enforce their policies - same reason why PLC was later disallowed from raising a standing army beyond a certain size by Russia; to keep it docile and easily controlled.
2) The actual morale of the nation, its armies and most importantly
the people interested in waging or defending against the war in the first place was low and this matters much more than how many warm bodies there are left to equip. In 1635 when PLC could've outright attacked Sweden and taken back more than just the Baltic ports on their lands lost in 1629, it didn't because the nobles just didn't want war, to fund war or (in accordance with 1) see the king's ambitions furthened.
3) Even though the nation
was more powerful on an absolute scale, it couldn't bring that to bear as effectively or efficiently as it'd like for different reasons, two being 1 and 2 of this post and others being things like logistical ability that aren't a concern in EU3. See Russia for an example of this, there has to be some explanation for why it
consistently during the 17th century failed to regain what it had lost in the Treaty of Stolbovo to Sweden and make any progress in Livonia, while earlier conflicts were pretty much stalemates that neither side won rather than the massive invasions we see in EU3.
4) Outside diplomatic pressure or involvement is non-existent in EU3 while in real life powers weren't interested in one nation eating up everything it wanted to unless it served their purposes. This doesn't happen in EU3 until after the peace deal is settled, and even then it's because of infamy, not because of traceable strategic reasons.
5) ... And so on.
Now that I think of it, I'd really like to read an explanation for why Russia couldn't just destroy Sweden (I don't care about the particular example but the reasons - Russia and Sweden just happens to be a very good example to explain what I want to learn about). Does anyone actually have a thorough explanation of why a nation like Russia couldn't just gobble up a place like Sweden?