Just finished my Russia game, a few things I'd like to add (Keep in mind I'm using no DLC):

In regards to the mod as a whole:
>Vassal liberty desire is outrageous. Vassals with far fewer than 100% total province warscore cost and not even a tenth of my total army size are perpetually disloyal. Vassal feeding is not a viable option, its better to go for PU's (which are insanely easy to get in this mod) and feed them.
>Suzerainties can join your war enemies if they are allied to them. This is not a problem in my opinion. Except for the fact that the treaty option to make them your vassal is greyed out, saying that upon loss the country will become a vassal again. However, this does not happen if you separate peace the vassal, even if you forced them to make concessions.
>In the end game I am completely out of uses for military points. I think it would be wise to make deportation/eradicate options require mil points as a replacement for, or in addition to the corruption penalty.
>Requiring cores to build troops or boats is frustrating. I think that if you have a forcelimit building in the province you should be able to do so. If a coastal province has a LITERAL place for constructing ships, is contributing sailors and forcelimit to my country, it is bizarre that I cannot construct ships.
>Condition 3 for making a core: "An accepted culture within your culture group and all provinces which surround it are owned by you." Completely broken. Should be checked. Never have I seen that condition be satisfied.
>Realm management should to be more specific in a few places especially in regards to the results of actions. For example, it would be great to know how long a deportation is expected to take, how much development is going to be lost, where the development will end up, what the rebel size may be, etc. The realm management option should be this informational black hole. If it is supposed to improve strategic play and reduce the abstraction of the base game, it shouldn't be this mysterious.
>The guides for the mod are also vague and not helpful. Tell me more about government values, what passively effects these values, etc.
>Why do some regions give me the option to promote state culure while others do not?


In regards to Russia 1865, some things to point out and strategic discussion:
>I still haven't colonized all of Siberia, but it's come to my attention from a friend with DLC that Russia gets free colonies. But still, colonial growth in early years is literally negative during the winter.
>Still cannot see most of East Asia and the Americas. Again, using DLC you could request to share maps, but in the base game I can at least see the entire map by the end of the game.
>What is Tsar Power in the government values? DLC thing? No mention of it in the guides, no events. There's a decision unlocked when I reach 200 Tsar power, "continue centralization," however I've been stuck at 0 Tsar power since forever.
>Deportation is really good to use on the tartar lands. Most provinces are only 3-4 dev so you won't lose much, and if you deport strategically you can prop up provinces with important trade goods or trade modifiers. Doing this allows you to make plenty of cores, save accepted culture slots, not waste money and time on conversion, and completely avoid rebellion on the steppe.
>Because of deportation, religious ideas are pointless for Russia. Go innovative instead.
>Navies are pointless to build, at least on a large scale. You can't core any of the relatively high value provinces on the black sea without deportation, and therefore cannot build boats there. Just build enough boats to keep the pirates away.

Back again with some more feedback. I can confidently say I've put about 800 hours into the mod, and I'm looking forward to playing more. I just want to go over two nations in particular, and the gameplay revolving around their unique regions and government types. Keep in mind that I do not play with DLC.

Starting with Milan, I'll try to include everything I can as it has been some time since I last played the campaign. For whatever reason an update corrupted the save, and I lost all my diplomatic relations. This is to be expected from playing across multiple versions of the game, and not necessarily a problem with the mod.
>PUs are insanely easy to get in the mod. I find that 60 year old rulers are less likely to miraculously conceive a child. As a Northern Italian state, the PU game is insanely easy to get HRE clay
>The Republic of Florence was doing this really weird thing. Every couple of years, The Duchy of Tuscany would get spit out from Florence, declare war on Florence, proceed to get annihilated, and fully annexed. The cycle repeated itself approximately 10 times; until I, who was growing tired of the repetitive calls to arms, decided to occupy the country myself to force a white peace. I then allied Tuscany, broke the alliance with Florence, and proceeded to shortly after get a free PU on Tuscany. Although this worked out in my favor, this is definitely the result of a bug.
>Why is Trent a part of the Empire, when all other Italian states are not? And why do I need it to fulfill missions leading to forming Italy?

Next with the Teutons, oh boy. Had lots of fun in the early and mid game, but my interest in continuing really began to dissolve once the broken features of the mod began to manifest.
>The decision to secularize does not work. I am forever stuck as a monastic order. I really wish I could've become a monarchy, expansion into the HRE would've been much less complicated. In addition, the event robbed me of my stability, which I couldn't get back for another 50 years.
>I complained about this almost a year ago: ">Condition 3 for making a core: "An accepted culture within your culture group and all provinces which surround it are owned by you." Completely broken. Should be checked. Never have I seen that condition be satisfied." I know you've looked at my post before, because you did fix the inability to create cores on the black sea as Russia, which I also lamented about! Because this key feature is broken, you cannot form Germany as not only the Teutons, but as any German state. This revelation was extremely upsetting.
>Conversion cost seems to increase rapidly over time. Some of my orthodox provinces take <24 months to convert, but cost around 2000 ducats monthly. These are not high dev provinces either, all being less than 200 dev
>Promote state culture is vague. Teutons/Prussia have solid ideas promoting culture spread, but I've had states with the "Promoting State Culture" modifier active for over 150 years, no results. Why not just bring back the ability to spend diplo points to convert provinces?

Now for some general observations.
>Whats the deal with development? Is one basegame dev supposed to be represented by 10 in the mod? Adding dev to low dev provinces can be very inexpensive (5-10 points) but once you hit around 150 dev it costs about the same as a single dev boost in the basegame, all for 1/10 the bonus. In other words, the benefit to developing provinces will be eclipsed by costs considerably quicker than in the basegame.
>More on development: events, missions, and decisions have not multiplied the dev increases by 10. Imagine getting the "Improve the capital" event, and having to spend a decent chunk of manpower or money for only one dev point. This also results in historical capitals being outpaced by backwater provinces from passive dev growth. (IE in my Teutons game, Anjou and Nigbolu had around 100 more dev than the capitals of their respective empires).
>I really feel strongly that army and navy units do not require a core to be built in a province. As long as a province has a RECRUITMENT CENTER (a place where troops are recruited and trained, they add forcelimit in game) or a DRYDOCK (a place where boats can be built, they add forcelimit in game), units should be able to be produced.
>Just because a game mechanic like dev growth or culture conversion is passive, it doesn't mean that it needs to work so abstractly. For example, why is dev growth expressed as a percent? What kind of useful information is a player expected to extrapolate? I recommend that the tooltips should express the MTTH of a passive event occurring, so there's less guesswork involved.

I'd recommend you join the discord, its a lot more active than these forums. A lot of experienced players can answer your questions there and you can provide direct feedback to Rivtal. https://discord.gg/qCpgyez