Over the last couple of weeks I've been playing Europa Universalis 3. A lot.
You could vaguely compare it to Total War games, but without battles, and with a lot more complex and deeper campaign mode. There's an obvious idea of mixing Total War style battles with EU3 style campaign, but EU3 is extremely complex and would probably be inaccessible to most casual players, and it would be far too easy, since any half-competent human player can crush AI in Total War battles even with significantly smaller armies.
So here's my list of issues with EU3, since do I ever do things in my reviews other than complain?
Infamy and StabilityThese two numbers are the main way game controls pacing of the campaign and prevents one country from just conquering the world right away.
You gain 4 infamy for each annexed territory and 4 extra for annexing whole country, and with really good reason you can get it to as low as 1 infamy per territory (like in a holy war). You also gain 4 infamy for forcing defeated enemy to become your vassal, and then 1 infamy per territory for annexing them later (but you also lose 1 stability, and all your other vassals strongly dislike you, so it's not that easy either). Your infamy can get pretty high before everybody gangs up to beat you, so it's not an immediate problem, but it takes forever to go down.
Stability has smaller scale of -3 to +3, and if you start a war without casus belli (-2), or against someone you have dynastic ties to (-1), or break truce (-5), or annex your vassal or country you're in personal union with (-1), or change domestic policy (anything from -1 to all the way down), it will make your stability hurt. Stability matters right away since it drastically increases revolt risk and lowers your income. It is relatively fast for small countries to recover, but extremely slow and expensive for big empires.
These two numbers mostly work well, but they often lead to extremely frustrating situations.
Annexing provinces which are core provinces of your country currently under someone else's control can cost 0 infamy, but only under some narrow circumstances - otherwise it's full 4 infamy penalty per province. I feel that's one thing which really needs fixing - even if you get only a partial discount without the right casus belli.
If you're attacked, then as defender you get to annex attacker's provinces at only 3 infamy each, but it doesn't always work, and for many defensive wars it's still full 4.
And generally any discounts you have only apply to your primary target - never to its allies, even if identical conditions apply to them as well (like reconquesting your core provinces, or holy war).
The game could really tweak these mechanics to reduce number of frustrating moments.
Or it could provide more ways to reduce your infamy. One thing I feel should really burn some is forcing others to release countries. That should be at least 1 infamy per released nation, or maybe even as much as 1 per released province + 1 extra for each released nation - and perhaps even a bit for forcing nations to free their vassals, but that might be getting too far.
Or there could be some decisions that you could use to convert prestige to infamy reduction at some steep rates. There are too many ways you can gain prestige (which maxes out at 100 anyway) - and there's little you can use it for other than expanding your sphere of influence, for some minor diplomatic bonuses. If annual infamy reduction used your total diplomacy (ruler skill + size of your sphere of influence), not just your ruler skill, that would be a really great prestige sink.
AgentsYou get some number of agents - diplomats, merchants, missionaries, colonists, spies, and magistrates. I don't have many issues with most of them - except diplomats are always in extremely short supply if you try to do anything interesting.
Seriously, diplomats should either be completely unlimited, or at least massively more plentiful. The way it is now, it's hard to do anything interesting when not at war, so you just sit there waiting for a diplomat to come while chasing rebels around the map.
It wouldn't lead to much abuse, since all diplomatic actions have some kind of associated cost - converting your diplomat to a general or admiral costs ton of money and army/naval tradition, while any diplomatic mission has limit of one a month per target country, and you get relations penalty if your proposal is refused.
So mostly not having enough diplomats is just annoying.
Peace talksAfter any war there are peace talks, where some of war's gains can become legitimate and permanent, while others revert to pre-war situation.
This of course, leads to some extremely annoying moments. First - only country which took a province can annex it - if any of your allies did so, you're screwed. Oh, you can force them to release that province, but you take the infamy hit, while they get the province.
And you cannot annex the country, unless you personally took every single one of their provinces. If you took 3 of 4 but your ally took the last one - screw you - no annexing for you for the next 5 years.
There have been far too many times when I wished my allies would just make a separate peace treaty and exit the war - either annexing that damn province they took, or releasing it so I can retake it myself, but they never felt like it.
Random missions and eventsThere are two things driving the game forward. First, there are your own goals, like uniting some particular country, defeating some nearby enemy, becoming the Holy Roman Emperor, or whatever you want.
Second - there are randomly generated missions and events. And very often these are the only thing moving the game forward. If you don't like a mission, you can cancel it for -5 prestige hit, but then you won't be able to cancel again for 5 more years.
I really wish it was possible to cancel mission more often, even while paying full prestige penalty. A lot of missions are either pretty much undoable - for example while playing as Burgundy with five coastal provinces, and fleet already over support limit, I was asked to "make larger fleet than England" - there's pretty much no way in hell to do so. Or to completely screw my standing in the empire by either attacking one of electors (who even happened to be my ally with royal ties and currently voting for me), or annexing some vassal on whom I don't have proper cores.
Or missions could be possible but they would take ridiculously long time. I had to convert Tangiers to Catholicism as Portugal, or convert all of Spain as Castille. This is all doable, but missionaries have low chance of success per year (like 5%/year), and there's no way to speed them up. So do you cancel the mission right away, or wait on average 20 years, or possibly a lot longer - Tangiers never converted in my entire over 100 years campaign.
The most annoying of all are missions requiring you to go to war with someone you just entered a truce, or even worse - you're already at war. Since your current war has wrong casus belli for the mission, you can either do what mission demands (annex something or vassalize them etc.) for a huge infamy hit - or finish current war, wait 5 years, and only then start a new one properly. Even assuming nothing will get you into another war with them in the meantime.
Quick fixesFortunately there are ways around this. First, there's lovely console where you can fix most of these issues.
For infinite diplomats, just use diplomat command - something I've been doing all the time anyway. You can also do that to other agent types, but I very rarely felt the need, other than when I was trying to figure out the mechanics.
You can also change infamy and stability this way - by commands like stability +3, infamy -8, etc. This gets quite solidly into cheating territory, but then if your choice is between infamy -20 and quitting the campaign out of frustration, go for it.
For stupid missions the easiest way is to edit save game file and delete the mission. Save file is a neatly formatted YAML-like text file - imagine that in this century - and it's super-easy to edit with any text editor.
Of course then you'll very often just get other stupid missions, so maybe the right fix is just add larger collection of sensible missions to the game, or tweak them so they are more appropriate.
I haven't been able to find even a very cheaty way of kicking an ally of territory the occupy, but that's probably just a matter of save game editing too.
Slow fixesThe game looks amazingly moddable - everything is just a bunch of text files with very little bullshit, so many of the issues I have I could probably solve by just writing a minimod - the same way I did with Medieval 2 Total War, Empire Total War (I never really released that one) etc.
Or maybe such minimod already exists somewhere. The game even has options for tweaking some settings - like making merchants cost 0 money, making colonists 4x faster etc. (both probably good ideas), but unfortunately not the ones I want.
If I ever get to do anything like that, I'll let you know.