About the adjustable AI worker requirement: The way this works is it adjusts the city count that the AI uses to evaluate how many workers it needs. So if it's set to 150, the AI builds workers as if it had 50% more cities than it actually does. The reason I added this was that I've thought for a long time that the AI could benefit by building more workers. Perfuming doesn't work well to make it build more since the AI assigns a point value of zero to the worker build option when it feels it has enough of them. The proper approach is to modify how many the AI thinks is enough.
Cool thing that you are looking into this, Flintlock. Building enough Workers is one of the areas where the human player can gain a major advantage over the AI, even at higher difficulty settings. I think your method of approach sounds just about right. This is why:
I ran some experiments about 2-3 years ago, to see if I could coerce the AI into building more Workers with the tools at my disposal at the time. More specifically, I tested whether setting the "Workers" flag under "Build often" in the vanilla Editor would have a measurable effect or not. And, whether it actually mattered how many "Build often" flags were set simultaneously, like 3, 4 or 5. I set up an experiment with a premade pangaea map, with only myself isolated on an unreachable island, and the Romans starting at a predetermined location on the main continent, without competition. Then I changed all the various parameters and let the Romans develop the continent fully multiple times (in Debug mode, so I could watch everything that was going on). My conclusions were:
Setting the "Build often" flag for Workers makes absolutely no difference. Because: The AI would always build a number of Workers equivalent to 80-90% of its number of cities at the peak of its development (49-57 Workers compared to 63 cities). It would never build more than that, no matter what. Then, as tile development progressed and the AI felt like it had redundant Workers, it would start killing them off. It did
not bother moving them into cities to either add to the population, or disband them there to gain some resources back. It simply disbanded them on the spot, as soon as they had finished clearing one of the last jungle tiles, for example. Have you ever noticed during gameplay, that sometimes you suddenly hear a loud "UHHH!" sound, and wonder what it was, because you can't see any combat going on? Well, that's the AI killing off its own Workers! The AI would always finish developing the last tile very close to the year 1945, no matter how I changed the parameters (turn 445 in my mod, which is quite late). In the end, after all tiles had been developed, the AI would keep a token force of 8-10 Workers around.
After the experiment, as the ability to perfume units became available with the C3X mod, that didn't do the trick either. Because the AI kills off Workers it doesn't want. So it doesn't matter if you force it to build more. This is why I think fooling the AI into thinking it actually needs more Workers is the right way to do this. With that approach, it is just a matter of finding the magic number, the sweet spot that works best with the AI. I'm looking forward to this improvement.