Have you wonder about how can a warrior that is disbanded can be a farmer. Next turn I need this warrior that knows how to farm into a merchant to then become a worker and finally a scientist.

I guess that is possible and yields of 6 makes sense a base. But it would be fun and realistic if the game rewards us for having citizens to improve as they don't change of specialization. Perhaps a small bonus can be received for having citizens employed in the same job. It would be nice to have citizens more individualized, perhaps you could tell who emigrated from another nation. Who was a warrior with multiple xp stars. That way we can create great people too.

Maybe disbanding units with 3 Star XP into a warrior based segment that improves the power of future units. Just throwing ideas here and there.

I think it doesn't make much sense, since between one shift and another it's not exactly days, but decades many times, so there wouldn't be a sudden change of profession, besides that it would add unnecessary micromanagement, maybe even exhausting in the bigger maps with populations of hundreds.

For this game, I don't think it would work.

But if you see Old World, it has what you are describing. When you gain population, they just become regular citizens, but you can train them to specialize in various things - like farming or temple or barracks, etc. After they are that, you cannot move them. It's more like infrastructure, but represented by population.