I have to note though, that generally I have been pleased with base BTS, mostly playing this mod because of AI and BUG mod. So any major overhauls of game mechanics are likely to alter things in way that I am not fond of.
I pretty much started modding because the original game was no longer worth playing to me. Even the major AI changes in the mod (war planning, relations modifiers) are aimed at shifting the game balance. It would've been wonderful if someone else had developed K-Mod in a spirit of preserving all the fundamentals (and most of the details) of BtS gameplay. That someone didn't materialize at the time nor since then.
I think that having countdown depend on size of occupying force is reasonable. Having cities endlessly remain in occupation is not fun. 3-4 turns is reasonable if I have 2-3 decent units in a modest city.
I agree, but the probabilistic duration based on the size of the occupying force currently really requires REVOLTS_IGNORE_CULTURE_RANGE because, otherwise, as you've pointed out earlier, most cities (those that can't revolt) get a 100% chance to decrease the timer, and it'll always start at 3. So maybe going back to the BtS mechanism (BASE_OCCUPATION_TURNS + OCCUPATION_TURNS_POPULATION_PERCENT * city size) is still better than that. Something like 2 + 33% * city size might work well enough for you.
Why exactly is oversupply of luxury resources a problem? Usually I am eager to import happiness resources as long as price is reasonable. There should always be civs interested in luxury resources as long as some of them don't have such resources. Price will drop of course.
With 1 happiness per unit, players usually won't find a buyer for their surplus luxury resources. For a quick test, I've run a game for 125 turns. My civ happened to have 3 Fur resources and 2 Ivory at that point. With 1 happiness per 2 units, 1 Fur was already being sold for 6 gold per turn and the other could've found a buyer for 4 gold per turn. The excess Ivory could've brought 6-8 gold iirc. After changing to 1 happiness per unit (and making sure through the DLL that the cached data gets updated) and running for another turn to ensure that everything got evaluated, no one wanted my third Fur. The existing Fur deal still had 5 turns to cancel. And Ivory dropped to 4 gpt. I don't want to go back to the AI paying baseless prices for unneeded resources.
If you have no surplus luxuries, this is of course not a noticeable problem. Though getting luxuries very cheaply on the world market is also not great for balance. I don't think Slavery should be seen as the baseline for what it should cost to manage unhappiness. If weakening HR indeed makes it unattractive to purchase luxury resources or to employ HR itself, then Slavery will just have to be nerfed harder or players should consider the mod's No Slavery option. That said, the mod already hurts Slavery-centric strategies through indirect measures such as the expanded revolt mechanism and reduced food near starting sites. The original effects of Slavery and HR are so efficient that happiness from religion, buildings and culture would need major buffs to compete with them.
I'd rather have HR grant happiness through buildings than through units. Killing the unit shuffling aspect entirely would perhaps also make up a little for the increased fiddliness of revolts. Unfortunately one of the most fitting buildings for such an extra happiness effect, the Monument, already has that effect via the Charismatic trait. Maybe something like extra happiness through the culture slider could work. Steps on the toes of the Odeon a bit. I feel it would have to be something convincing; otherwise better to leave it at a nerfed version of the original effect.
My preferred way of playing is to build sufficiently powerful army to completely conquer weakest neighbor while preserving enough of my army to keep steamrolling over rest of the civs from weakest to strongest in perpetual war until end of the game. I don't want to lose steam by having to stop conquest while my units get outdated and enemy builds defensive units.
And the mod deliberately aims to discourage that approach. If it still works – with boring obstructions that only delay the inevitable -, then the difficulty setting might be too low.
Currently culture revolt chance seems artificial and disproportionately strong. I pretty much had to keep 3/4 as many units as city has population to quench revolt chance. This is clearly too many from both gameplay and realism sense and makes it unfeasible to keep perpetual war campaign going. [...] In "Yorok AD-0760" savegame Lakamha revolted next turn which it definitely shouldn't, as it had archer and longbow guarding 4 population.
Population size itself isn't that big a factor, but it tends to correlate with city culture. As for realism, Lakhamha in your savegame has 19 passable tiles around it, all with significant Mayan cultural influence, a majority in 14 of them. Plenty of room for a rebellion to organize – and get much better equipped than an Ancient-era Archer unit. The game's "real population" formula shows a population of 48,500 for Lakahma. How many men might a Medieval military unit represent, a thousand?
Generally I would like to see AI building proper SODs (50% siege - currently they build too few siege units) and use them in defensive wars against attackers by attacking first (thanks to roads in own culture) - first with siege, then with rest of units. Usually AI does random attacks with scattered siege units, which is a complete waste because they don't attack immediately afterwards with non-siege units, so I can heal damage off.
The AI currently has no notion that being the attacker is crucial for bringing collateral damage to bear. (
This post of mine sketches a way to improve this.) So I don't think more siege units would make a human invader sweat. The attacks by individual siege units I see as a mere delaying tactic; healing in enemy territory is slow. (May also be that these attacks happen at times for no justifiable reason.)
It is clunky to have to exit trade screen, temporarily alter research rate, enter trade screen, make trade, exit trade screen and alter research rate back to previous level. Also I sometimes forget that I have to do this. And I can't do this at all when it happens during AI turn?
Do you mean by "income determines the AI proposals", that if player doesn't have enough income, then AI doesn't offer some deals, it would otherwise offer?
When you ask the AI "What will you give me for this?", the AI could sometimes offer either (only) gold or (also) something else (probably a resource or tech). I think the BtS behavior was to always offer something else. In AdvCiv you can lower your gold rate so that you run a deficit (no need to exit the diplo screen for that), and then the AI will offer only gold (and something else only if all its gold isn't enough). Anyway, it would sure be an improvement if the Gold Per Turn shown on the player's side of the trade table would get updated immediately when the player's gold rate changes. That would eliminate the need to exit and re-engage. Just letting the player offer more gold also sounds reasonable. I suppose there should be some limit. Not sure how precisely the game can predict the income for hypothetical slider positions. Something like (at least) one tenth of the stored gold could also be consideration – one tenth because the deal is supposed to last for at least ten turns. The diplo screen is difficult to modify because it's implemented in the EXE. Maybe none of this is easily possible; I'll try to check.
Hmm, usually I don't see any missionary. I just see a notification, that one religion has spread to the city while other one has disappeared from it. [...]
You're right, passive spread also has a chance of removing an existing religion. I had trouble finding the code for that when I wrote my previous post. The (K-Mod) removal chance in that case is based on an obscure "religion grip" value that expresses how well established a religion is (buildings, state religion status, distance to Holy City/ Shrine) - and on the total number of religions present. Maybe that chance is indeed too high. For example, in this screenshot,
... Confucianism has replaced Buddhism in London. The odds for removing Buddhism were 20% based on the difference in grip values (although the Holy City of Buddhism is closer than the one for Confucianism, i.e. Thebes), taken times 2 because the present religions are counted after the spread of Confucianism. This latter part sounds accidental, and the grip calculation is also dubious. I'll investigate further.
I have a lot of work for workers in captured lands, because I usually convert captured cities to workshop-powered production cities. Often I find unimproved tiles. AIs build too many non-resource farms, which need to be replaced with more useful improvements. [...]
If you run the Workshop civics, then, sure, you'll want to convert conquered lands.
Hmm, Solid Shoreline indeed gets rid of trap-peninsulas, but as a side-effect makes the map kinda boring

Is there indeed considerably less seafood next to main landmass than with other shoreline types, or am I imagining things? I think that amount of seafood next to main landmass should not depend on islands.
If a less scraggly shoreline is shorter, then there will be fewer eligible tiles for seafood and less seafood will be placed.
I am unsure what ENABLE_STARTING_POSITION_ITERATION exactly does and should I really disable it. [...] I could disable ENABLE_STARTING_POSITION_ITERATION, but what are side effects?
A lot of text about this under change id 027 in the manual. There's also
this old thread. The side-effect is probably that the available space for expansion gets partitioned less evenly in the majority of the cases. But you might get rid of the cases that you find the most objectionable this way.
Civ, which starts isolated, is crippled, which is especially bad if it is human and still bad if is AI (less variety in game). In my example Alexander was basically out of the game the entire time.
It's just one out of 7 rivals though – with the BtS default player counts, you'd only have 6 rivals anyway. If civs were never placed in isolation, then the main landmasses would get overcrowded. (Although, if it's just one island with room for 5 cities, then this should not be too much of an issue.) An isolated civ that fares poorly is a potential target for a late conquest – a chance for civs on the main continent(s) that aren't powerful enough to expand there. Whether and when to search for an isolated civ in order to establish trade can also be an interesting consideration.
Why in "Yorok AD-1500" savegame has Peter not sent more of his units (there are plenty of units all around his empire, especially in Verlamion) to his SOD (2 tiles SW of Bibracte)? It ended with disaster like can be seen in "Yorok AD-1530 - Railroad" savegame. Sending more units would surely have let him capture Tolosa and maybe Bibracte.
The Four Knights of Verlamion are assigned the "pillage" unit AI type. They don't see anything worth pillaging in Boudica's territory that they can reach within 3 turns. Her single Iron Mine is apparently just out of reach. Looks like they got a bit too far away from the action somehow. This might be a good place (in the AI code) for converting some pillagers to a city attack role. The unit AI types are normally largely static and already set when a city decides to train a unit. If it's trained for the purpose of pillaging (and harassment, opportunistic attacks), that'll be it's dharma for life. One of the major shortcomings of the AI. Anyway, I agree that those four Knights should somehow get involved. In a quick test, getting the Knights to move in the 1500 save immediately distracts some of Boudica's units around Bibracte and indeed results in Russia conquering Tolosa.