Very interesting analysis and thoughts, thanks.
I am a tad confused though.. is it possible you're confusing me for someone else? You responded to my comments here in this thread of course. But then you made multiple references to an MP thread that I don't know if I've even read - and certainly not all the way through - let alone commented in
Though I don't know if it's a result of Multi-player testing(though it very well could be from Johan's comment)
Could you link me to his comment? I haven't read it.
I get your point, it's hard to determine if X,Y, or Z feature was a result of MP testing.
I have never made any points related to MP testing

My points in this thread, when I quoted you, was about strategy/gameplay versus historical plausibility. I don't care about historicality so I don't mind if features have no basis in reality. I just want them to be fun and strategic and challenging.
But that's not an MP/SP point, because I only play SP (thus far). I want features that require me to strategise and plan in my single player games, and I don't mind if they then end up having no relation to reality. For example being a single button press to do something major like cultural shifting. As long as pressing that button has implications that I have to weigh up, and as long as there's enough different kinds of buttons to press, and sufficient complexity and subtlety behind deciding when and what to press, and why, such as to give the player sufficient choice and control and resulting in the whole thing requiring thought and planning and the formation of strategies.
I will concede that I don't. Though, like I said, Johan said that most testing has been done in MP since EU2. There have been really good points in that thread on how SP and MP testing don't necessarily result in mutually exclusive results.
I didn't know that and, as an exclusively SP player, it worries me somewhat! It also seems a little odd. Although MP is important, it seems to me highly likely that the vast majority of player-hours in EU4 will be in SP. It should therefore have the preponderance of test hours.
There's that recent thread (and maybe it's the one you're referring to re Johan comments?), about "Sire should I kick you in the head" or whatever - someone in that thread, upon viewing the recent MP video, said "it seems clear to me now that MP is the focus." That took me by surprise. I still haven't watched that video, and I should . But it surprised me because, having read these forums for two months and read thousands of posts, I never got that impression before. I could count on the fingers of one hand the number of times I read a dev say "this feature is mostly there for MP players." In fact the first time I saw reference to that was just a couple of days ago - re Enforced Peace, Wiz explained that the option to accept an Enforced Peace (thus ending the war, without the sender getting added to the war) was never used by the AI, and the possibility existed only for MP games. That sounded perfectly fine for me; OK the AI can't handle doing that (and Wiz explained why - it was too hard to get the AI to accept it intelligently, it was a huge exploit), so for SP games it's just a "join this war" button, but with humans it can work either way. Fair enough, that sounds to me like a balance of SP/MP that's just fine.
So that's why it'd never occurred to me that MP might be a focus. I'd never seen lots of comments along the lines of "yeah that feature is only for MP". But if indeed they do most of their testing only in MP, then that does sound rather different to what I expected; whether or not they're deliberately prioritising MP over SP, the mere fact that they apparently don't test SP nearly as much means that they are going to end up prioritising MP by default.
EDIT: I think this is one of the games major flaws. In MP you're focused on conquest, when this era was about so much more than that. So it stands to reason that certain mechanics would be implemented because their lens is one of MP where everyone is out to conquer one another; to win per se. Players, like me, who set their own goals and achievements don't need to go warmongering to have fun or to prove something. Sure, the goal to conquer your neighbor should be available, but so should the option of building your country into a great economic power as a goal unto itself.
I fully agree that the game should be about more than just conquest. For different reasons than you - I don't care about the historicality, I just want a varied and interesting and fun and strategic game. EU4 is all of those things (times a million) for me already; but I think it could be even better if there was more stuff to do that didn't revolve around conquest. Not because the conquest stuff is in any way bad for me - just because more is almost always better, and more varied is even better.
One of EU4's great strengths, for me, is that I can rotate between different types of gameplay, different kinds of challenges, different physical things to do of varying types - require varying skills and priorities and thought processes. But they do all mostly come back to conquest, or facilitating conquest. So variations that have nothing to do with conquest - for example, dealing with internal politics/factions - would undoubtedly be a good thing, and would extend the game's appeal even further for me.
Sorry that this post is rather rambly, very tired and need to go to bed - but was both confused and interested in your references to this MP debate, which I've not really been involved in but would like to know more about.